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Plant Products as Antimicrobial Agents
The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.
Cowan, Marjorie Murphy
Plant Antimicrobial Agents and Their Effects on Plant and Human Pathogens
To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of several phytoalexins and phytoanticipins defending plants against fungal and bacterial aggressors and those with antibacterial activities against pathogens affecting humans such as Pseudomonas aeruginosa and Staphylococcus aureus involved in respiratory infections of cystic fibrosis patients. The utility of plant products as "antibiotic potentiators" and "virulence attenuators" is also described as well as some biotechnological applications in phytoprotection.
Gonzalez-Lamothe, Rocio; Mitchell, Gabriel; Gattuso, Mariza; Diarra, Moussa S.; Malouin, Francois; Bouarab, Kamal
Anthocyanins as antimicrobial agents of natural plant origin.
Anthocyanins are particularly abundant in different fruits, especially in berries. The beneficial effects of these compounds for human health have been known from at least the 16th century. Despite the great number of papers devoted to the different biological effects exerted by anthocyanins only a limited number of studies is focused on the antimicrobial activity of these compounds. Anthocyanin content of berry fruits varies from 7.5 mg/100 mg fresh fruit in redcurrant (Ribes rubum) up to 460 mg/100 g fresh fruit in chokeberry (Aronia melanocarpa). After consumption, anthocyanins are intensively metabolized, mainly in the intestines and liver. Glucorination, methylation and sulfation are the most typical metabolic reactions. Antimicrobial activity of crude extracts of plant phenolic compounds against human pathogens has been intensively studied to characterize and develop new healthy food ingredients as well as medical and pharmaceutical products. However, there is very little information available about the antimicrobial activity of the pure anthocyanins. In the last part of this review we present the collection of papers describing the anthocyanin profiles of different fruits (mainly berries) and the antimicrobial properties of the identified compounds. Generally, anthocyanins are active against different microbes, however Gram-positive bacteria usually are more susceptible to the anthocyanin action than Gram-negative ones. Mechanisms underlying anthocyanin activity include both membrane and intracellular interactions of these compounds. Antimicrobial activity of berries and other anthocyanin-containing fruits is likely to be caused by multiple mechanisms and synergies because they contain various compounds including anthocyanins, weak organic acids, phenolic acids, and their mixtures of different chemical forms. Therefore, the antimicrobial effect of chemically complex compounds has to be critically analyzed. PMID:21366068
Cisowska, Agnieszka; Wojnicz, Dorota; Hendrich, Andrzej B
Medicinal plants and antimicrobial activity
In the present paper, we analyze the past, present and future of medicinal plants, both as potential antimicrobial crude drugs as well as a source for natural compounds that act as new anti-infection agents. In the past few decades, the search for new anti-infection agents has occupied many research groups in the field of ethnopharmacology. When we reviewed the number
J. L. Ríos; M. C. Recio
Fluoroquinolone antimicrobial agents.
The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections.
Wolfson, J S; Hooper, D C
Investigational antimicrobial agents of 2013.
New antimicrobial agents are always needed to counteract the resistant pathogens that continue to be selected by current therapeutic regimens. This review provides a survey of known antimicrobial agents that were currently in clinical development in the fall of 2012 and spring of 2013. Data were collected from published literature primarily from 2010 to 2012, meeting abstracts (2011 to 2012), government websites, and company websites when appropriate. Compared to what was reported in previous surveys, a surprising number of new agents are currently in company pipelines, particularly in phase 3 clinical development. Familiar antibacterial classes of the quinolones, tetracyclines, oxazolidinones, glycopeptides, and cephalosporins are represented by entities with enhanced antimicrobial or pharmacological properties. More importantly, compounds of novel chemical structures targeting bacterial pathways not previously exploited are under development. Some of the most promising compounds include novel ?-lactamase inhibitor combinations that target many multidrug-resistant Gram-negative bacteria, a critical medical need. Although new antimicrobial agents will continue to be needed to address increasing antibiotic resistance, there are novel agents in development to tackle at least some of the more worrisome pathogens in the current nosocomial setting. PMID:24092856
Pucci, Michael J; Bush, Karen
Impact of edible coating with or without anti-microbial agent on microbial growth during osmotic dehydration and refrigerated storage of a model plant material
The use of edible coating has proved a valuable tool in improving the efficiency of osmotic dehydration (OD) of plant material. In this study the impact of edible coating with or without an anti-microbial agent (A–M) on microbial growth was investigated. Potato cylinders (15×57 mm — D×L) were used as a model plant material. Calcium alginate (CA) coating was applied with
G. E. Mitrakas; K. P. Koutsoumanis; H. N. Lazarides
Proarrhythmic Potential of Antimicrobial Agents
Several antiarrhythmic and non-cardiovascular drug therapies including antimicrobial agents have been implicated as the causes\\u000a for QT interval prolongation, torsades de pointes (TdP) ventricular tachycardia and sudden cardiac death. Most of the drugs\\u000a that have been associated with the lengthening of the QT interval or development of TdP can also block the rapidly activating\\u000a component of the delayed rectifier potassium
J. Simkó; A. Csilek; J. Karászi; I. L?rincz
Secondary Metabolites from Plants Inhibiting ABC Transporters and Reversing Resistance of Cancer Cells and Microbes to Cytotoxic and Antimicrobial Agents
Fungal, bacterial, and cancer cells can develop resistance against antifungal, antibacterial, or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: (1) Activation of ATP-binding cassette (ABC) transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, (2) Activation of cytochrome p450 oxidases which can oxidize lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulfate, or amino acids, and (3) Activation of glutathione transferase, which can conjugate xenobiotics. This review summarizes the evidence that secondary metabolites (SM) of plants, such as alkaloids, phenolics, and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria, and fungi. Among the active natural products several lipophilic terpenoids [monoterpenes, diterpenes, triterpenes (including saponins), steroids (including cardiac glycosides), and tetraterpenes] but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids) function probably as competitive inhibitors of P-gp, multiple resistance-associated protein 1, and Breast cancer resistance protein in cancer cells, or efflux pumps in bacteria (NorA) and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones) directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse multidrug resistance, at least partially, of adapted and resistant cells. If these SM are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion.
Wink, Michael; Ashour, Mohamed L.; El-Readi, Mahmoud Zaki
Anatomical barriers for antimicrobial agents.
It is often suggested that there are substantial anatomic barriers to the passage of antibiotics from the circulation into tissues and fluids of the body. In fact, most capillary beds are fenestrated and allow the passage of antimicrobial agents into tissue fluids fairly readily. At equilibrium, the mean concentrations of free (unbound) antibiotic in plasma and tissue fluids over the dosing interval are equal. However, the time to achieve equilibrium may range from minutes to days, depending on the ratio of surface area to volume of the tissue fluid compartment. There are several sites in the body in which nonfenestrated capillary beds pose appreciable barriers to the diffusion of antibiotics, namely the central nervous system, the eye and the prostate gland. Only lipid-soluble drugs traverse these capillaries readily. If the nonporosity of the capillaries were the only barrier to drug diffusion in these sites, the mean concentrations would eventually be equal to those in the plasma. However, in the central nervous system and the retina of the eye, transport pumps for organic anions combine with the effect of nonporous capillaries to produce concentrations which, even at equilibrium, are lower than those in the plasma. Bulk flow may also play a role in lowering drug concentrations in the cerebrospinal fluid. In the prostate gland, pH partition may cause mean concentrations in the prostatic secretions to differ from those in the plasma at equilibrium. PMID:8477760
Barza, M
Sensitivity of environmental microorganisms to antimicrobial agents.
The sensitivity of different microorganisms, considered as typical representatives of the microflora of soil and water, was established to evaluate the influence of the nonmedical use of antimicrobial agents on bacterial ecology. Only seven strains, six chemoorganotrophs and one chemolithotroph, could be considered as relatively sensitive to the 21 antimicrobial compounds tested. The other 29 microorganisms may be regarded as resistant to most antimicrobial agents. Streptomyces were sensitive to high concentrations of active substances. Broad-spectrum antibiotics showed an effect on environmental bacteria similar to that on human pathogens. Cephalothin stimulated the growth of a Chlorella sp. From these experiments, it appears that spilled antimicrobial agents have little chance of causing an alteration in the microbial ecology.
Van Dijck, P; van de Voorde, H
Antimicrobial Activities of the Essential Oils of Various Plants against Tomato Late Blight Disease Agent Phytophthora infestans
The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete\\u000a pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic\\u000a plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp.
E. Mine Soylu; Soner Soylu; Sener Kurt
Protease inhibitors from plants with antimicrobial activity.
Antimicrobial proteins (peptides) are known to play important roles in the innate host defense mechanisms of most living organisms, including plants, insects, amphibians and mammals. They are also known to possess potent antibiotic activity against bacteria, fungi, and even certain viruses. Recently, the rapid emergence of microbial pathogens that are resistant to currently available antibiotics has triggered considerable interest in the isolation and investigation of the mode of action of antimicrobial proteins (peptides). Plants produce a variety of proteins (peptides) that are involved in the defense against pathogens and invading organisms, including ribosome-inactivating proteins, lectins, protease inhibitors and antifungal peptides (proteins). Specially, the protease inhibitors can inhibit aspartic, serine and cysteine proteinases. Increased levels of trypsin and chymotrypsin inhibitors correlated with the plants resistance to the pathogen. Usually, the purification of antimicrobial proteins (peptides) with protease inhibitor activity was accomplished by salt-extraction, ultrafiltration and C(18) reverse phase chromatography, successfully. We discuss the relation between antimicrobial and anti-protease activity in this review. Protease inhibitors from plants potently inhibited the growth of a variety of pathogenic bacterial and fungal strains and are therefore excellent candidates for use as the lead compounds for the development of novel antimicrobial agents. PMID:19582234
Kim, Jin-Young; Park, Seong-Cheol; Hwang, Indeok; Cheong, Hyeonsook; Nah, Jae-Woon; Hahm, Kyung-Soo; Park, Yoonkyung
Susceptibility of Lactobacillus spp. to antimicrobial agents.
Bacteria used as probiotics or in starter cultures may serve as hosts of antibiotic resistance genes, which can be transferred to pathogenic bacteria. Before launching a starter culture or a probiotic product into the market, it is therefore important to verify that the single bacterial isolates (strains) do not contain transferable resistance genes. A study has been undertaken to establish the levels of susceptibility of Lactobacillus spp. to various antimicrobial agents. This is a prerequisite for differentiating putative transferable resistance from natural resistance. A selection of 62 strains has been screened with the use of the Etest (ABBiodisk, Stockholm, Sweden) for their susceptibility to 25 antimicrobial agents. The strains belonged to the following species: Lactobacillus plantarum/pentosus, L. rhamnosus, L. paracasei, L. sakei, L. curvatus and species of the L. acidophilus group: L. johnsonii, L. crispatus, L. gasseri, and L. acidophilus. The results from the Etests have shown that the level of susceptibility to the antimicrobial agents is species-dependent. For the following antimicrobial agents, susceptibility varied several folds between species: vancomycin, teicoplanin, tetracycline, norfloxacin, ciprofloxacin, fusidic acid, and clindamycin. The differences between the species were more subtle for the rest of the tested antimicrobial agents. On the basis of the result, it was possible to suggest minimal inhibition concentrations (MICs) for the individual Lactobacillus species to be used as a microbiological breakpoint when screening strains for transferable resistance genes. PMID:12505455
Danielsen, Morten; Wind, Anette
[Staphylococcus aureus: new and old antimicrobial agents].
The objective of the study was to evaluate the susceptibility to old and new antimicrobial agents against hospital-acquired oxacillin-resistant Staphylococcus aureus (HA-ORSA), community-acquired oxacillin-resistant S. aureus (CA-ORSA), and oxacillin-susceptible S. aureus(OSSA). The minimum inhibitory concentration of different antimicrobial agents against 118 S. aureus consecutive and prospective isolates was studied by the CLSI agar dilution method. In ORSA isolates without accompanying resistance, the mecA gene, the Panton-Valentine leukocidin gene (PVL), and the gamma-hemolysin gene were determined by PCR, and the SCC cassette mec gene by multiplex PCR. Out of the 118 isolates, 44 were HA-ORSA, 16 were CA-ORSA, and 58 corresponded to OSSA. The HA-ORSA isolates presented simultaneous resistance to erythromycin, clindamycin, gentamicin, ciprofloxacin, levofloxacin, and moxifloxacin whereas all of them were susceptible to tigecycline (TIG), vancomycin, teicoplanin and linezolid (LZD). The CA-ORSA isolates were only resistant to OXA and presented susceptibility to all the antimicrobial agents assayed. In all of them, the mec-A gene, the PVL gene, the gamma-hemolysin gene and the SCC cassette mec type IV gene were detected. With the OSSA and CA-ORSA isolates, all the non-beta-lactam antimicrobial agents assayed exhibited excellent in vitro activity. However, in the HA-ORSA isolates, only the old antimicrobial agents such as glycopeptides, doxyciclin, rifampin, and trimethoprim-sulfamethoxazole and the new antimicrobial agents LZD and TIG, presented good in vitro activity. The ORSA phenotype without accompanying resistance was highly predictive of CA-ORSA as confirmed by a positive SCC cassette mec type IV. PMID:21186674
Perazzi, B; Camacho, M; Bombicino, K; Flores, Z; Vay, C; Famiglietti, A
Polymers containing antimicrobial agents and methods for making and using same
US Patent & Trademark Office Database
Polymeric compositions containing antimicrobial agents and methods for making and using same are provided. The antimicrobial agents include phytochemicals and phytonutrients such as naturally occurring extracts from plants and herbs and other chemical disinfectants safe for use on food-contact surfaces. Chemical releasers can be added to the compositions for causing the release of the antimicrobial agents. The chemical releasers include citric acid extract. A blend of antimicrobial agents can be included in the composition for destroying and inhibiting the growth of a wide variety of different microorganisms including bacteria, viruses, and fungi.
Dihydrofolate reductase and cell growth activity inhibition by the beta-carboline-benzoquinolizidine plant alkaloid deoxytubulosine from Alangium lamarckii: its potential as an antimicrobial and anticancer agent.
Beta-carboline-benzoquinolizidine plant alkaloid deoxytubulosine (DTB) was evaluated and assessed for the first time for its biochemical and biological activity employing the biomarker dihydrofolate reductase (DHFR) (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 184.108.40.206) as the probe enzyme, a key target in cancer chemotherapy. DHFR, employed in the present investigations was purified from Lactobacillus leichmannii. DTB, isolated from the Indian medicinal plant Alangium lamarckii was demonstrated to exhibit potent cytotoxicity. The alkaloid potently inhibited the cell growth of L. leichmannii and the cellular enzyme activity of DHFR (IC50=40 and 30 microM for the cell growth and enzyme inhibitions, respectively). DTB concentrations >75 microM resulted in a total loss of the DHFR activity, thus suggesting that the beta-carboline-benzoquinolizidine plant alkaloid is a promising potential antitumor agent. Our results are also suggestive of its potential antimicrobial activity. DTB binding to DHFR appears to be slow and reversible. Inhibition kinetics revealed that DHFR has a Ki value of 5x10(-6) M for DTB and that the enzyme inhibition is a simple linear 'non-competitive' type. PMID:10428380
Rao, K N; Venkatachalam, S R
Linezolid: an oxazolidinone antimicrobial agent
Background: Linezolid is the first oxazolidinone anti-infective agent marketed in the United States. It is indicated for the treatment of nosocomial pneumonia, complicated skin and skin-structure infections caused by methicillin-sensitive or methicillin-resistant Staphylococcus aureus and other susceptible organisms, and vancomycin-resistant Enterococcus faecium infections. It also is indicated for the treatment of uncomplicated skin and skin-structure infections caused by methicillin-sensitive S
Horatio B. Fung; Harold L. Kirschenbaum; Babatunde O. Ojofeitimi
Stability of antimicrobial agents in peritoneal dialysate.
The stability of cephapirin, gentamicin, penicillin G, nafcillin, ticarcillin, and vancomycin was tested in peritoneal dialysate at 25 degrees C for 24 h. All of the antimicrobial agents were stable except penicillin G, which lost 25% of activity over 24 h (P less than 0.01). The once-daily preparation of drug-dialysate solution is feasible for the treatment of peritonitis in patients on continuous ambulatory peritoneal dialysis.
Sewell, D L; Golper, T A
Antimicrobial topical agents used in the vagina.
Vaginally applied antimicrobial agents are widely used in the vagina in women with lower genital tract infections. An 'antimicrobial' is a general term that refers to a group of drugs that are effective against bacteria, fungi, viruses and protozoa. Topical treatments can be prescribed for a wide variety of vaginal infections. Many bacterial infections, such as bacterial vaginosis, desquamative inflammatory vaginitis or, as some European authors call it, aerobic vaginitis as well as infection with Staphylococcus aureus or group A streptococci, may be treated in this way. Candida vulvovaginitis is a fungal infection that is very amenable to topical treatment. The most common viral infections which can be treated with topical medications are condylomata acuminata and herpes simplex. The most often encountered protozoal vaginitis, which is caused by Trichomonas vaginalis, may be susceptible to topical medications, although this infection is treated systemically. This chapter covers the wide variety of commonly used topical antimicrobial agents for these diseases and focuses on the individual therapeutic agents and their clinical efficacy. In addition, potential difficulties that can occur in practice, as well as the usage of these medications in the special setting of pregnancy, are described in this chapter. PMID:21325838
Frey Tirri, Brigitte
Bdellovibrio bacteriovorus : A future antimicrobial agent?
Bdellovibrio and like organisms (BALOs) are small, predatory, Deltaproteobacteria that prey on other Gram-negative pathogens. Many authors have unfolded the possible use of BALOs as biological control agents in environmental as well as medical microbiological settings. They are found strongly associated with natural biofilms and recent studies have shown that effective predation occurs in these naturally occurring bacterial communities. Periodontal infections could also be an interesting target for the application of BALOs as biological Gram-negative bacteria and therefore potentially susceptible to BALOs antimicrobial agents. This proposition is based on the fact that almost all periodontal pathogens are predation. Accordingly, this review aims to present the evolution toward applying Bdellovibrio bacteriovorus as an antibacterial agent to deal with oral infections, general medical conditions, environmental and industrial issues. PMID:24554900
Harini, K; Ajila, Vidya; Hegde, Shruthi
Discovery and development of new antimicrobial agents.
The unprecedented growth in the number of new antibiotics over the past two decades has been the result of extensive research efforts that have exploited the growing body of knowledge describing the interactions of antibiotics with their targets in bacterial cells. Information gained from one class of antimicrobial agents has often been used to advance the development of other classes. In the case of beta-lactams, information on structure-activity relationships gleaned from penicillins and cephalosporins was rapidly applied to the cephamycins, monobactams, penems, and carbapenems in order to discover broad-spectrum agents with markedly improved potency. These efforts have led to the introduction of many new antibiotics that demonstrate outstanding clinical efficacy and improved pharmacokinetics in humans. The current review discusses those factors that have influenced the rapid proliferation of new antimicrobial agents, including the discovery of new lead structures from natural products and the impact of bacterial resistance development in the clinical setting. The development process for a new antibiotic is discussed in detail, from the stage of early safety testing in animals through phase I, II, and III clinical trials.
Gootz, T D
Cotton fabric finished with ?-cyclodextrin: Inclusion ability toward antimicrobial agent.
?-Cyclodextrin was grafted onto cotton fabric through crosslinking with butane tetracarboxylic acid in presence of sodium hypophosphite monohydrate as a catalyst. This finished cotton fabric was loaded with the antimicrobial agent octenidine dihydrochloride. ?-Cyclodextrin-grafted cotton fabrics, both after loading with octenidine dihydrochloride or before loading (control) were characterized for their antimicrobial activity against two types of bacteria (Gram positive and Gram negative) and two types of fungi, using the Diffusion Disk Method. The antimicrobial cotton fabric was subjected to several washing cycles and the antimicrobial activity was measured after each washing cycle to examine the durability of this antimicrobial finishing against repeated washing. The measurements showed that the finished cotton fabrics retain reasonable deal of their antimicrobial activity, even after 20 washing cycles. This long-lasting antimicrobial activity is attributed to the hosting ability of the cavities present in cyclodextrin moieties, which host the antimicrobial agent molecules and release them gradually. PMID:24507318
Abdel-Halim, E S; Al-Deyab, Salem S; Alfaifi, Ali Y A
The therapeutic monitoring of antimicrobial agents
Aims To review the basis and optimal use of therapeutic drug monitoring of antimicrobial agents. Methods Antimicrobial agents for which a reasonable case exists for therapeutic drug monitoring were reviewed under the following headings: pharmacokinetics, why monitor, therapeutic range, individualisation of therapy, sampling times, methods of analysis, interpretative problems and cost-effectiveness of monitoring. Results There is a strong historical case for monitoring aminoglycosides. The recent move to once-daily dosing means that criteria for therapeutic drug monitoring need to be redefined. Vancomycin has been monitored routinely but many questions remain about the most appropriate approach to this. A case can be made for monitoring teicoplanin, flucytosine and itraconazole in certain circumstances. Conclusions The approach to monitoring aminoglycosides needs to be redefined in the light of once-daily dosing. It is premature to suggest that less stringent monitoring is necessary as toxicity remains a problem with these drugs. The ideal method of monitoring vancomycin remains to be defined although a reasonable case exists for measuring trough concentrations, mainly to ensure efficacy. Teicoplanin is monitored occasionally to ensure efficacy while flucytosine is monitored occasionally to avoid high concentrations associated with toxicity. Itraconazole has various pharmacokinetic problems and monitoring has been suggested to ensure that adequate concentrations are achieved.
Begg, Evan J; Barclay, Murray L; Kirkpatrick, Carl J M
Antimicrobial activity of South African medicinal plants.
This paper reviews the antimicrobial research undertaken on South African medicinal plants during the period 1997-2008. Antimicrobial methods (disc diffusion, minimum inhibitory concentration (MIC), bio-autography) are briefly discussed and an analysis of the publications reviewed indicates that the majority of papers use MIC assays for antimicrobial determination. Antimicrobial investigations on extracts are presented where the most active plants are identified from screening publications. A summary of some bioactive compounds are given with data restricted to papers reporting quantitative antimicrobial activity equivalent to or below 200 microg/ml. Antimicrobial activities on the essential oils of indigenous medicinal aromatic plants are also reviewed. An overview is given on what activities (extracts, compounds and oils) should be considered noteworthy for publication. Studies focusing on geographical ethnobotany, specific pathogenesis, formulation aspects and in vivo investigations are examined. Future recommendations to consider include pathogen selection, interactive studies and dosage administrations. PMID:18582553
van Vuuren, S F
Aetiology of antimicrobial-agent-associated colitis.
Clostridium difficile was isolated from the faeces of a patient with clindamycin-associated pseudomembranous colitis (P.M.C.). The presence of a preformed faecal toxin and the toxigenicity of both the faecal isolate of C. difficile and a reference strain of C. difficile were demonstrated by tissue-culture assay. The toxin of both strains of C. difficile and that in the patient's faeces were neutralised by heating and by incubation with antitoxin to C. sordellii, but not by incubation with antitoxin to C. histolyticum, C. oedematiens (novyi), C. welchii (C. perfringens) or C. septicum. These data implicate the toxin of C. difficile as a major, and perhaps the sole, cause of antimicrobial-agent-associated P.M.C. of man and suggest that the neutralisation of the faecal toxin of P.M.C. by C. sordellii antitoxin, as described by other investigators, may be a non-specific phenomenon. PMID:85818
George, W L; Sutter, V L; Goldstein, E J; Ludwig, S L; Finegold, S M
Silanols, a New Class of Antimicrobial Agent.
National Technical Information Service (NTIS)
Alkyldimethylsilanols, R(CH3)2SiOH, were recently reported to exhibit unexpectedly strong antimicrobial effects. The antimicrobial activities of alkyldimethylsilanols were significantly higher than their analogous alcohols. A study of structural dependenc...
R. H. Baney S. Farrah Y. Kim
Susceptibility of Legionella species to antimicrobial agents.
Thirty-five clinical isolates of Legionella species were tested against 7 antimicrobial agents using an agar dilution technique. Results obtained on charcoal-supplemented (BCYE) and charcoal-free agar (BSYE) were compared. On BCYE, the most active agent was rifampicin; the minimal inhibitory concentration inhibiting 90% of the strains (MIC90) was 0.008 mg/L. Imipenem was the next most active in vitro (MIC90 0.06 mg/L). The macrolide antibiotics and ciprofloxacin also inhibited the organisms at low concentrations (MIC90 < or = 2 mg/L). In general, MIC's obtained on BCYE agar were at least twofold higher than on BSYE agar except for that of imipenem. BSYE agar is a suitable alternative medium for susceptibility testing of most Legionella species. Erythromycin and rifampicin continue to demonstrate good in vitro activity against legionellae in Australia. On the basis of in vitro susceptibility tests, the other macrolides and ciprofloxacin are likely to be suitable alternatives for the treatment of legionellosis. PMID:8367199
Chen, S C; Paul, M L; Gilbert, G L
Antimicrobial activity of selected Peruvian medicinal plants.
The antimicrobial activity of 36 ethanol extracts from 24 plants, all of them currently used in the Peruvian traditional medicine for the treatment of several infectious and inflammatory disorders, was tested by means of the agar-well diffusion assay against four bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and four fungi (Candida albicans, Trichophyton mentagrophytes, Microsporum gypseum and Sporothrix schenckii). Twenty-five (69%) extracts showed some degree of antimicrobial activity against at least one microorganism. The plants with the greatest antimicrobial activity were Cestrum auriculatum L. Heritier (Solanaceae), Iryanthera lancifolia Ducke Suesseng (Myristicaceae), Lepechinia meyenii (Walp.) Epling (Lamiaceae) and Ophryosporus peruvianus (Gmelin) King & H. Rob. (Asteraceae). PMID:12963143
Rojas, Rosario; Bustamante, Beatriz; Bauer, José; Fernández, Irma; Albán, Joaquina; Lock, Olga
De-Novo Design of Antimicrobial Peptides for Plant Protection
This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobial agents and with the increasing demand for antimicrobial compounds for production of "healthy" food, these peptides might serve as templates for novel antibacterial and antifungal agents.
Zeitler, Benjamin; Herrera Diaz, Areli; Dangel, Alexandra; Thellmann, Martha; Meyer, Helge; Sattler, Michael; Lindermayr, Christian
Antimicrobial agents, drug adverse reactions and interactions, and cancer.
The intent of this chapter is to review the types of adverse drug reactions and interactions associated with antimicrobial agents, specifically in the setting of patients with malignancies. The initial sections will discuss categorizing and describing the mechanisms of adverse reactions and interactions. The later sections include a detailed discussion about adverse reactions and drug interactions associated with commonly used antibacterial, antiviral, and antifungal agents in this subpopulation. Where relevant, the clinical use and indication for the drugs will be reviewed. The antibacterial section will specifically address the emergence of antimicrobial resistance and drugs of last resort (newer agents, such as linezolid and daptomycin and novel uses of older previously retired agents, such as polymyxin B). The antifungal section will address the ramification of pharmacokinetic interactions and the need to measure drug levels. The chapter is not meant to be exhaustive and as such will not extensively address all antimicrobials or all interactions for each of these agents. PMID:24706233
Millan, Ximena; Muggia, Victoria; Ostrowsky, Belinda
Antimicrobial effects of Thai medicinal plants against acne-inducing bacteria
Propionibacterium acnes and Staphylococcus epidermidis have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Thai medicinal plants against these etiologic agents of acne vulgaris. Crude extracts were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion method showed that 13
Mullika Traidej Chomnawang; Suvimol Surassmo; Veena S. Nukoolkarn; Wandee Gritsanapan
Controlled fermentation of kimchi using naturally occurring antimicrobial agents.
Kimchi is a traditional Korean fermented food. Since it ferments continuously during distribution and storage, the extension of shelf life by preventing over-acidification is a major concern in the kimchi industry. One of the most frequently attempted ways to delay fermentation is to add naturally occurring antimicrobial agents. Many researchers have investigated ways to delay over-acidification by adding minor ingredients, fruits or fruit seed extracts, extracts of medicinal herbs, culinary herbs and spices, and other miscellaneous substances to kimchi. The addition of naturally occurring antimicrobial agents may enhance the acceptability of kimchi to consumers over a longer period of time but may also have a disadvantage in that it may cause changes in sensory quality, especially if added in large amounts. To avoid undesirable sensory changes, application of hurdle technologies (i.e., multifactor preservative systems) which involve using combinations of low amounts of various naturally occurring antimicrobial agents as ingredients should be explored with the goal of controlling fermentation. If synergistic or additive antimicrobial effects can be achieved using small amounts of a combination of natural agents, changes in sensory qualities will be minimized, thereby prolonging shelf life. Research findings summarized in this review provide a basis for developing effective hurdle technologies using naturally occurring antimicrobial agents to extend shelf life of kimchi and perhaps other types of traditional fermented foods. PMID:22850370
Kim, Jinsol; Bang, Jihyun; Beuchat, Larry R; Kim, Hoikyung; Ryu, Jee-Hoon
In vitro susceptibility of Trichomonas vaginalis to 50 antimicrobial agents.
We determined the susceptibilities of five strains of Trichomonas vaginalis, one of which was metronidazole resistant, to 50 antimicrobial agents. For the metronidazole-susceptible strains, the most active agents were metronidazole, tinidazole, mebendazole, furazolidone, and anisomycin. Against the resistant strain mebendazole, furazolidone, and anisomycin were the most active. Antifungal agents, beta-lactams, macrolides, aminoglycosides, and folic acid antagonists were ineffective against all strains.
Sears, S D; O'Hare, J
Quaternized Chitosan as an Antimicrobial Agent: Antimicrobial Activity, Mechanism of Action and Biomedical Applications in Orthopedics
Chitosan (CS) is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobial agent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered.
Tan, Honglue; Ma, Rui; Lin, Chucheng; Liu, Ziwei; Tang, Tingting
Antimicrobial and cytotoxic effects of Mexican medicinal plants.
The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC50 < or = 30 microg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents. PMID:22312741
Jacobo-Salcedo, Maria del Rosario; Alonso-Castro, Angel Josabad; Salazar-Olivo, Luis A; Carranza-Alvarez, Candy; González-Espíndola, Luis Angel; Domínguez, Fabiola; Maciel-Torres, Sandra Patricia; García-Lujan, Concepción; González-Martínez, Marisela del Rocio; Gómez-Sánchez, Maricela; Estrada-Castillón, Eduardo; Zapata-Bustos, Rocio; Medellin-Milán, Pedro; García-Carrancá, Alejandro
Antimicrobial Spectrum of Triclosan, a Broad-Spectrum Antimicrobial Agent for Topical Application
The antimicrobial activity of 5-chloro-2(2,4-dichlorophenoxy) phenol (triclosan, one of the active ingredients of Logamel®, Ciba-Geigy) was compared in vitro with that of other antimicrobials exclusively or occasionally used as topical agents in dermatology: hexachlorophene, clioquinol, chlorquinaldol. gentamicin, neomycin, nystatin, econazole, clotrimazole and salicylic acid. Upon determination of the MICs for 53 strains of aerobic and anaerobic bacteria, yeasts and fungi,
J. Regös; O. Zak; R. Solf; W. A. Vischer; E. G. Weirich
Using Silver Nanoparticles as an Antimicrobial Agent
\\u000a Antimicrobial and antifungal properties of silver nanoparticles, silver ions, acrylate paint and cotton fabric impregnated\\u000a with Ag nanoparticles were assessed against Escherichia coli (Gram-negative bacterium); Staphylococcus aureus and Bacillus subtilis (Gram-positive bacteria); Aspergillus niger, Aureobasidium pullulans and Penicillium phoeniceum (cosmopolitan saprotrophic fungi). The silver ions used in the bacterial susceptibility tests were released from pure silver\\u000a electrodes using a 12
R. R. Khaydarov; R. A. Khaydarov; S. Evgrafova; Y. Estrin
Mushrooms as Possible Antioxidant and Antimicrobial Agents
The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 ?g/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 ?g/mL), BHA (IC50 = 6.42 ?g/mL) and ?-tocopherol (IC50 = 62.43 ?g/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases.
Kosanic, Marijana; Rankovic, Branislav; Dasic, Marko
Use of surrogate antimicrobial agents to predict susceptibility to ertapenem
Broth or agar dilution susceptibility test results for Enterobacteriaceae (11,775 strains), anaerobes (2888 strains), staphylococci (2206 strains), Haemophilus spp. (840 strains), group A streptococci (280 strains), group B streptococci (269 strains), Streptococcus pneumoniae (709 strains), and 160 other streptococci were analyzed to identify surrogate antimicrobial agents to predict susceptibility to ertapenem. Ertapenem MIC interpretive categories approved by the United States
Ian R. Friedland; Robin Isaacs; Lori A. Mixson; Mary Motyl; Gail L. Woods
Resistance to Antimicrobial Agents in Lactobacilli Isolated from Caper Fermentations
A collection of lactobacilli comprising species of Lactobacillus plantarum (43 isolates), Lactobacillus brevis (9 isolates) and Lactobacillus fermentum (6 isolates) obtained from spontaneous fermentations of capers (the fruits of Capparis spinosa) were investigated for resistance to antimicrobial agents. All isolates were resistant to vancomycin and teicoplanin (MIC > 16 ?g\\/ml). Resistance to ciprofloxacin (MIC > 2 ?g\\/ml) was detected in
Rubén Pérez Pulido; Nabil Ben Omar; Rosario Lucas; Hikmate Abriouel; Magdalena Martínez Cańamero; Antonio Gálvez
Antimicrobial Peptides as Infection Imaging Agents: Better Than Radiolabeled Antibiotics
Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.
Akhtar, Muammad Saeed; Imran, Muhammad Babar; Nadeem, Muhammad Afzal; Shahid, Abubaker
Fabatins: new antimicrobial plant peptides.
Two new antimicrobial peptides related to the gamma-thionine family have been isolated by acid extraction from the broad bean Vicia faba. The extract was separated by ion exchange chromatography, and a fraction showing antibacterial activity was further purified by reverse-phase HPLC. Material from a single HPLC peak was sequenced and revealed the presence of two peptides differing by one amino acid. The peptides were named fabatins. They are 47 amino acids long, have an overall positive charge and contain 8 cysteines that probably form 4 disulfide bridges characteristic of the gamma-thionins. Fabatins were active against both Gram-negative and Gram-positive bacteria, but were inactive against the yeasts Saccharomyces cerevisiae and Candida albicans. PMID:9103978
Zhang, Y; Lewis, K
Chemerin Is an Antimicrobial Agent in Human Epidermis
Chemerin, a chemoattractant ligand for chemokine-like receptor 1 (CMKLR1) is predicted to share similar tertiary structure with antibacterial cathelicidins. Recombinant chemerin has antimicrobial activity. Here we show that endogenous chemerin is abundant in human epidermis, and that inhibition of bacteria growth by exudates from organ cultures of primary human skin keratinocytes is largely chemerin-dependent. Using a panel of overlapping chemerin-derived synthetic peptides, we demonstrate that the antibacterial activity of chemerin is primarily mediated by Val66-Pro85, which causes direct bacterial lysis. Therefore, chemerin is an antimicrobial agent in human skin.
Banas, Magdalena; Zabieglo, Katarzyna; Kasetty, Gopinath; Kapinska-Mrowiecka, Monika; Borowczyk, Julia; Drukala, Justyna; Murzyn, Krzysztof; Zabel, Brian A.; Butcher, Eugene C.; Schroeder, Jens M.; Schmidtchen, Artur; Cichy, Joanna
Antimicrobial properties of Honduran medicinal plants.
Ninety-two plants used in the traditional pharmacopoeia of the Pech and neighboring Mestizo peoples of central Honduras are reported. The results of in vitro antimicrobial screens showed that 19 of the extracts from medicinal plants revealed signs of antifungal activity while 22 demonstrated a measurable inhibitory effect on one or more bacterial cultures. Bioassay-guided fractionation of extracts from Mikania micrantha, Neurolaena lobata and Piper aduncum produced weak to moderately active isolates. The broad spectrum of activity of the extracts helps to explain the widespread use of these plants for wound healing and other applications. PMID:10030730
Lentz, D L; Clark, A M; Hufford, C D; Meurer-Grimes, B; Passreiter, C M; Cordero, J; Ibrahimi, O; Okunade, A L
Systemic anti-microbial agents used in periodontal therapy
Periodontitis is an infectious disease with marked inflammatory response, leading to destruction of underlying tissues. The aim of periodontal therapy is to eradicate the pathogens associated with the disease and attain periodontal health. This is achieved by non-surgical and surgical therapy; however, mechanical debridement and topical application of antiseptics may not be helpful in all cases. In such cases, adjunctive systemic antibiotic therapy remains the treatment of choice. It can reach micro-organisms at the base of the deep periodontal pockets and furcation areas via serum, and also affect organisms residing within gingival epithelium and connective tissue. Before advising any anti-microbial agent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbial agent used in periodontal therapy. The points discussed are its mode of action, susceptible periodontal pathogens, dosage, its use in treatment of periodontal disease, and mechanism of bacterial resistance to each anti-microbial agent. It might be of some help while prescribing these drugs.
Patil, Vishakha; Mali, Rohini; Mali, Amita
Antimicrobial potential of some plant extracts against Candida species.
The increase in the resistance to antimicrobial drugs in use has attracted the attention of the scientific community, and medicinal plants have been extensively studied as alternative agents for the prevention of infections. The Candida genus yeast can become an opportunistic pathogen causing disease in immunosuppressive hosts. The purpose of this study was to evaluate dichloromethane and methanol extracts from Mentha piperita, Rosmarinus officinalis, Arrabidaea chica, Tabebuia avellanedae, Punica granatum and Syzygium cumini against Candida species through the analysis of Minimum Inhibitory Concentration (MIC). Results presented activity of these extracts against Candida species, especially the methanol extract. PMID:21180915
Höfling, J F; Anibal, P C; Obando-Pereda, G A; Peixoto, I A T; Furletti, V F; Foglio, M A; Gonçalves, R B
Effective Treatment of Folliculitis Decalvans Using Selected Antimicrobial Agents
Folliculitis Decalvans (FD) is a rare neutrophilic infammation of the scalp characterized by painful, recurrent purulent follicular exudation resulting in primary cicatricial alopecia. However, unclear etiology makes FD treatment a difficult task. A wide variety of topical and systemic agents have been tried previously, with varied results. We present here a case series report of a set of 13 patients with FD on antimicrobial therapy.
Sillani, Caulloo; Bin, Zhang; Ying, Zhao; Zeming, Cai; Jian, Yang; Xingqi, Zhang
Improved agar diffusion method for detecting residual antimicrobial agents.
The improved agar diffusion method for determination of residual antimicrobial agents was investigated, and the sensitivities of various combinations of test organisms and assay media were determined using 7 organisms, 5 media, and 31 antimicrobial agents. Bacillus stearothermophilus and synthetic assay medium (SAM) showed the greatest sensitivity for screening penicillins (penicillin G and ampicillin). The combination of Bacillus subtilis and minimum medium (MM) was the most sensitive for tetracyclines (oxytetracycline and chlortetracycline), B. stearothermophilus and SAM or Micrococcus luteus and Mueller-Hinton agar (MHA) for detecting tylosin and erythromycin, B. subtilis and MHA for aminoglycosides (streptomycin, kanamycin, gentamicin, and dihydrostreptomycin), B. stearothermophilus and SAM for polyethers (salinomycin and lasalocid), and B. subtilis and MM or Clostridium perfringens and GAM for polypeptides (thiopeptin, enramycin, virginiamycin, and bacitracin). However, gram-negative bacterium Escherichia coli ATCC 27166 and MM were better for screening for colistin and polymixin-B. For detecting the synthetic drugs tested, the best combination was B. subtilis and MM for sulfonamides, E. coli 27166 and MM for quinolones (oxolinic acid and nalidixic acid), B. subtilis and MM for furans (furazolidone), and the bioluminescent bacterium Photobacterium phosphoreum and luminescence assay medium for chloramphenicol and oxolinic acid. The results showed that the use of four assay plates, B. stearothermophilus and SAM, B. subtilis and MM, M. luteus and MHA, and E. coli 27166 and MM, was superior to the currently available techniques for screening for residual antimicrobial agents in edible animal tissues. PMID:11252480
Tsai, C E; Kondo, F
In vitro antifungal properties of mouthrinses containing antimicrobial agents.
The purpose of this study was to investigate the in vitro antifungal properties of seven commercial mouthrinses containing antimicrobial agents. These included cetylpyridinium chloride (CPC), chlorhexidine digluconate (CHX), hexetidine (HEX), sanguinarine (SNG), and triclosan (TRN). The minimum fungicidal concentration (MFC) against six species of yeasts was determined by a broth macrodilution method. The kill-time of mouthrinses at half the concentration of the commercial formulations was also determined. MFCs were achieved with each mouthrinse, except the SNG-containing mouthrinse, against all the organisms being tested. However, the CPC-containing mouthrinse appeared more active than the other products (P < 0.001). There were no significant differences in MFC values among CHX mouthrinse products, once adjusted for initial concentration differences (P = 0.1). Kill-times of mouthrinses containing either CHX or CPC were less than or equal to 180 seconds with all the species of yeasts, and no significant differences were found among these products (P = 0.18). On the other hand, mouthrinses containing either TRN or HEX did not show a lethal effect on Candida albicans, Candida parapsilosis, or Candida guilliermondii. No kill-times were achieved with the SNG-containing mouthrinse. These results suggest that mouthrinses containing antimicrobial agents might represent an appropriate alternative to conventional antifungal drugs in the management of oral candidiasis. However, the effectiveness of antimicrobial mouthrinses as antifungal agents needs to be evaluated in further clinical trials. PMID:9287062
Giuliana, G; Pizzo, G; Milici, M E; Musotto, G C; Giangreco, R
Antimicrobial activity of some medicinal plants from Ghana.
The results of a preliminary antimicrobial screening of the methanol extracts of Aframomum melegueta, Piper guineense, Xylopia aethiopica, Zingiber officinale, medicinal plants of Ghana, are reported. PMID:14693222
Konning, G H; Agyare, C; Ennison, B
Antimicrobial resistance of fecal indicators in municipal wastewater treatment plant.
Antimicrobial resistance of fecal coliforms (n = 153) and enterococci (n = 199) isolates was investigated in municipal wastewater treatment plant (WWTP) based on activated sludge system. The number of fecal indicators (in influent and effluent as well as in the aeration chamber and in return activated sludge mixture) was determined using selective media. Susceptibility of selected strains was tested against 19 (aminoglycosides, aztreonam, carbapenems, cephalosporins, ?-lactam/?-lactamase inhibitors, fluoroquinolones, penicillines, tetracycline and trimethoprim/sulfamethoxazole) and 17 (high-level aminoglycosides, ampicillin, chloramphenicol, erythromycin, fluoroquinolones, glycopeptides, linezolid, lincosamides, nitrofuration, streptogramins, tetracycline) antimicrobial agents respectively. Among enterococci the predominant species were Enterococcus faecium (60.8%) and Enterococcus faecalis (22.1%), while remaining isolates belonged to Enterococcus hirae (12.1%), Enterococcus casseliflavus/gallinarum (4.5%), and Enterococcus durans (0.5%). Resistance to nitrofuration and erythromycin was common among enterococci (53% and 44%, respectively), and followed by resistance to ciprofloxacin (29%) and tetracycline (20%). The resistance phenotypes related to glycopeptides (up to 3.2%) and high-level aminoglycosides (up to 5.4%) were also observed. Most frequently, among Escherichia coli isolates the resistance patterns were found for ampicillin (34%), piperacillin (24%) and tetracycline (23%). Extended-spectrum ?-lactamase producing E. coli was detected once, in the aeration chamber. In the study the applied wastewater treatment processes considerably reduced the number of fecal indicators. Nevertheless their number in the WWTP effluent was higher than 10(4) CFU per 100 ml and periodically contained 90% of bacteria with antimicrobial resistance patterns. The positive selection of isolates with antimicrobial resistance patterns was observed during the treatment processes. Substantial concern should be paid to the isolates resistant to 3 or more chemical classes of antimicrobials (MAR). In treated wastewater MAR E. coli and MAR enterococci constituted respectively 9% and 29% of tested isolates. PMID:20810144
?uczkiewicz, A; Jankowska, K; Fudala-Ksi??ek, S; Ola?czuk-Neyman, K
Antimicrobial Susceptibilities of Aeromonas Strains Isolated from Clinical and Environmental Sources to 26 Antimicrobial Agents
We determined the susceptibilities of 144 clinical and 49 environmental Aeromonas strains representing 10 different species to 26 antimicrobial agents by the agar dilution method. No single species had a predominantly nonsusceptible phenotype. A multidrug nonsusceptible pattern was observed in three (2.1%) clinical strains and two (4.0%) strains recovered from diseased fish. Common clinical strains were more resistant than the corresponding environmental isolates, suggesting that resistance mechanisms may be acquired by environmental strains from clinical strains.
Inglis, Timothy J. J.; Henderson, Barbara; Riley, Thomas V.; Chang, Barbara J.
Electrospun composite nanofiber fabrics containing uniformly dispersed antimicrobial agents as an innovative type of polymeric materials with superior antimicrobial efficacy.
Herein we report that electrospun composite nanofiber fabrics containing uniformly dispersed antimicrobial agents and having large surface-to-mass ratios are an innovative type of antimicrobial polymeric materials with durable, nonleachable, and biocompatible characteristics, and more importantly, superior antimicrobial efficacy. Specifically, electrospun cellulose acetate (CA) nanofiber fabrics containing an N-halamine antimicrobial agent of bis(N-chloro-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Cl-BTMP) were prepared and evaluated; the results of antimicrobial efficacy indicated that the electrospun composite nanofiber fabrics substantially outperformed the control samples that were solution-cast films containing identical amounts of CA and Cl-BTMP. Additionally, the results of trypan blue assay test suggested that the electrospun composite nanofiber fabrics also had excellent mammal cell viability. The developed electrospun composite nanofiber fabrics with superior antimicrobial efficacy are expected to find vital applications in biomedical, hygienic, and many other fields. PMID:20380426
Sun, Xinbo; Zhang, Lifeng; Cao, Zhengbing; Deng, Ying; Liu, Li; Fong, Hao; Sun, Yuyu
Bacterial cell wall compounds as promising targets of antimicrobial agents I. Antimicrobial peptides and lipopolyamines
The first barrier that an antimicrobial agent must overcome when interacting with its target is the microbial cell wall. In the case of Gram-negative bacteria, additional to the cytoplasmic membrane and the peptidoglycan layer, an outer membrane (OM) is the outermost barrier. The OM has an asymmetric distribution of the lipids with phospholipids and lipopolysaccharide (LPS) located in the inner and outer leaflets, respectively. In contrast, Gram-positive bacteria lack OM and possess a much thicker peptidoglycan layer compared to their Gram-negative counterparts. An additional class of amphiphiles exist in Gram-positives, the lipoteichoic acids (LTA), which may represent important structural components. These long molecules cross-bridge the entire cell envelope with their lipid component inserting into the outer leaflet of the cytoplasmic membrane and the teichoic acid portion penetrating into the peptidoglycan layer. Furthermore, both classes of bacteria have other important amphiphiles, such as lipoproteins, whose importance has become evident only recently. It is not known yet whether any of these amphiphilic components are able to stimulate the immune system under physiological conditions as constituents of intact bacteria. However, all of them have a very high pro-inflammatory activity when released from the cell. Such a release may take place through the interaction with the immune system, or with antibiotics (particularly with those targeting cell wall components), or simply by the bacterial division. Therefore, a given antimicrobial agent must ideally have a double character, namely, it must overcome the bacterial cell wall barrier, without inducing the liberation of the pro-inflammatory amphiphiles. Here, new data are presented which describe the development and use of membrane-active antimicrobial agents, in particular antimicrobial peptides (AMPs) and lipopolyamines. In this way, essential progress was achieved, in particular with respect to the inhibition of deleterious consequences of bacterial infections such as severe sepsis and septic shock.
de Tejada, Guillermo Martinez; Sanchez-Gomez, Susana; Kowalski, Ina; Kaconis, Yani; Andra, Jorg; Schurholz, Tobias; Hornef, Mathias; Dupont, Aline; Garidel, Patrick; Gutsmann, Thomas; David, Sunil A.; Brandenburg, Klaus
Essential oils and their principal constituents as antimicrobial agents for synthetic packaging films.
Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs. PMID:22416718
Kuorwel, Kuorwel K; Cran, Marlene J; Sonneveld, Kees; Miltz, Joseph; Bigger, Stephen W
Antimicrobial activity of some ethnomedicinal plants used by Paliyar tribe from Tamil Nadu, India
Background Antimicrobial activity of 18 ethnomedicinal plant extracts were evaluated against nine bacterial strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Ervinia sp, Proteus vulgaris) and one fungal strain (Candida albicans). The collected ethnomedicinal plants were used in folk medicine in the treatment of skin diseases, venereal diseases, respiratory problems and nervous disorders. Methods Plants were collected from Palni hills of Southern Western Ghats and the ethnobotanical data were gathered from traditional healers who inhabit the study area. The hexane and methanol extracts were obtained by cold percolation method and the antimicrobial activity was found using paper disc diffusion method. All microorganisms were obtained from Christian Medical College, Vellore, Tamil Nadu, India. Results The results indicated that out of 18 plants, 10 plants exhibited antimicrobial activity against one or more of the tested microorganisms at three different concentrations of 1.25, 2.5 and 5 mg/disc. Among the plants tested, Acalypha fruticosa, Peltophorum pterocarpum, Toddalia asiatica,Cassia auriculata, Punica granatum and Syzygium lineare were most active. The highest antifungal activity was exhibited by methanol extract of Peltophorum pterocarpum and Punica granatum against Candida albicans. Conclusion This study evaluated the antimicrobial activity of the some ethnomedicinal plants used in folkloric medicine. Compared to hexane extract, methanol extract showed significant activity against tested organisms. This study also showed that Toddalia asiatica, Syzygium lineare, Acalypha fruticosa and Peltophorum pterocarpum could be potential sources of new antimicrobial agents.
Duraipandiyan, Veeramuthu; Ayyanar, Muniappan; Ignacimuthu, Savarimuthu
Susceptibilities of bovine summer mastitis bacteria to antimicrobial agents.
The susceptibility to 9 antimicrobial agents of 32 aerobic bacterial isolates and to 10 antimicrobial agents of 37 anaerobic bacterial isolates from 23 cases of bovine summer mastitis (16 Actinomyces pyogenes isolates, 8 Streptococcus dysgalactiae isolates, 3 S. uberis isolates, 3 S. acidominimus isolates, 2 Streptococcus spp., 15 Peptostreptococcus indolicus isolates, 10 Fusobacterium necrophorum isolates, and 12 isolates of anaerobic gram-negative rods) was determined by the agar dilution method. All isolates except one Bacteroides fragilis isolate (beta-lactamase producer) were susceptible to penicillin G, amoxicillin, amoxicillin-clavulanate, cefoxitin, clindamycin, and chloramphenicol (the B. fragilis strain was susceptible to the last four), which had MICs at which 90% of isolates were inhibited (MIC90s) of < or = 0.06, < or = 0.06, < or = 0.06 0.25, < or = 0.06, and 4.0 micrograms/ml, respectively. Spiramycin was active against the gram-positive aerobes (MIC90, 1.0 microgram/ml) but not against the anaerobes (MIC90, 16.0 micrograms/ml). Similar trends were noted for susceptibilities of aerobic and anaerobic bacteria to ofloxacin (MIC90s, 2.0 and 8 micrograms/ml, respectively). Occasional strains of aerobic streptococci were resistant to oxytetracycline, but all anaerobes were susceptible. Tinidazole was active against all anaerobes (MIC90, 2.0 micrograms/ml). beta-Lactamase was produced only by the B. fragilis isolate.
Jousimies-Somer, H; Pyorala, S; Kanervo, A
Susceptibilities of bovine summer mastitis bacteria to antimicrobial agents.
The susceptibility to 9 antimicrobial agents of 32 aerobic bacterial isolates and to 10 antimicrobial agents of 37 anaerobic bacterial isolates from 23 cases of bovine summer mastitis (16 Actinomyces pyogenes isolates, 8 Streptococcus dysgalactiae isolates, 3 S. uberis isolates, 3 S. acidominimus isolates, 2 Streptococcus spp., 15 Peptostreptococcus indolicus isolates, 10 Fusobacterium necrophorum isolates, and 12 isolates of anaerobic gram-negative rods) was determined by the agar dilution method. All isolates except one Bacteroides fragilis isolate (beta-lactamase producer) were susceptible to penicillin G, amoxicillin, amoxicillin-clavulanate, cefoxitin, clindamycin, and chloramphenicol (the B. fragilis strain was susceptible to the last four), which had MICs at which 90% of isolates were inhibited (MIC90s) of < or = 0.06, < or = 0.06, < or = 0.06 0.25, < or = 0.06, and 4.0 micrograms/ml, respectively. Spiramycin was active against the gram-positive aerobes (MIC90, 1.0 microgram/ml) but not against the anaerobes (MIC90, 16.0 micrograms/ml). Similar trends were noted for susceptibilities of aerobic and anaerobic bacteria to ofloxacin (MIC90s, 2.0 and 8 micrograms/ml, respectively). Occasional strains of aerobic streptococci were resistant to oxytetracycline, but all anaerobes were susceptible. Tinidazole was active against all anaerobes (MIC90, 2.0 micrograms/ml). beta-Lactamase was produced only by the B. fragilis isolate. PMID:8787898
Jousimies-Somer, H; Pyörälä, S; Kanervo, A
Antimicrobial agents for treatment of serious infections caused by resistant Staphylococcus aureus and enterococci
As clinicians increasingly contend with infections due to staphylococci or enterococci resistant to, or failing treatment\\u000a with, traditional antimicrobial agents, understanding the potential roles of older as well as more recently introduced antimicrobial\\u000a agents becomes important. Older agents, such as clindamycin and trimethoprim-sulfamethoxazole, have been used to treat infections\\u000a due to community-acquired methicillin-resistant Staphylococcus aureus. Among the licensed agents, quinupristin-dalfopristin,
G. M. Eliopoulos
Susceptibility of Campylobacter jejuni to twenty-three antimicrobial agents.
Twenty-three antimicrobial agents, including 4 new broadspectrum beta-lactam antibiotics were tested against 50 clinical isolates of Campylobacter jejuni. The activity of metabolites of metronidazole and tinidazole was also tested. Minimum inhibitory concentrations (MIC) were determined by agar dilution. beta-lactamase production was detected by a chromogenic cephalosporin method. All strains were susceptible to erythromycin, clindamycin, chloramphenicol, furazolidone, aminoglycosides (including gentamicin), cefotaxime and NF-thienamycin. All isolates were resistant to penicillin, cephalothin, cefoperazone, vancomycin, rifampicin and trimethoprim; beta-lactamase was detected in 2% of isolates. Some strains were resistant and others sensitive to the other drugs tested, which included ampicillin, moxalactum tetracycline, metronidazole and tinidazole. The 'hydroxy' metabolites of metronidazole and tinidazole were more active than the parent compounds. PMID:6602320
Shanker, S; Sorrell, T C
Resistance to antimicrobial agents in lactobacilli isolated from caper fermentations.
A collection of lactobacilli comprising species of Lactobacillus plantarum (43 isolates), Lactobacillus brevis (9 isolates) and Lactobacillus fermentum (6 isolates) obtained from spontaneous fermentations of capers (the fruits of Capparis spinosa) were investigated for resistance to antimicrobial agents. All isolates were resistant to vancomycin and teicoplanin (MIC > 16 microg/ml). Resistance to ciprofloxacin (MIC > 2 microg/ml) was detected in all isolates of L. brevis and L. fermentum as well as in most isolates of L. plantarum, whilst resistance to levofloxacin showed a much lower incidence. Among L. plantarum and L. brevis isolates, low levels of resistance to tetracycline and/or nitrofurantoin were detected. Higher resistance levels were also detected in some isolates. Resistance to penicillin and rifampicin were also detected among L. plantarum isolates. All isolates were sensitive to ampicillin, erythromycin, chloramphenicol, gentamicin, streptomycin, and quinupristin/dalfopristin. PMID:16284934
Pérez Pulido, Rubén; Omar, Nabil Ben; Lucas, Rosario; Abriouel, Hikmate; Martínez Cańamero, Magdalena; Gálvez, Antonio
Novel Zinc(II) Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies
The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria: E. coli and Pseudomonas fluorescens, Gram positive bacteria: Staphylococcus aureus, and also against fungi, that is, C. albicans and A. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2??g/mL). The "in vitro" data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents against C. albicans and A. niger.
Yamgar, Ramesh S.; Nivid, Y.; Nalawade, Satish; Mandewale, Mustapha; Atram, R. G.; Sawant, Sudhir S.
Antimicrobial peptide genes in Bacillus strains from plant environments.
The presence of the antimicrobial peptide (AMP) biosynthetic genes srfAA (surfactin), bacA (bacylisin), fenD (fengycin), bmyB (bacyllomicin), spaS (subtilin), and ituC (iturin) was examined in 184 isolates of Bacillus spp. obtained from plant environments (aerial, rhizosphere, soil) in the Mediterranean land area of Spain. Most strains had between two and four AMP genes whereas strains with five genes were seldom detected and none of the strains had six genes. The most frequent AMP gene markers were srfAA, bacA, bmyB, and fenD, and the most frequent genotypes srfAA-bacA-bmyB and srfAAbacA- bmyB-fenD. The dominance of these particular genes in Bacillus strains associated with plants reinforces the competitive role of surfactin, bacyllomicin, fengycin, and bacilysin in the fitness of strains in natural environments. The use of these AMP gene markers may assist in the selection of putative biological control agents of plant pathogens. PMID:22569759
Mora, Isabel; Cabrefiga, Jordi; Montesinos, Emilio
Multidrug Pump Inhibitors Uncover Remarkable Activity of Plant Antimicrobials
Plant antimicrobials are not used as systemic antibiotics at present. The main reason for this is their low level of activity, especially against gram-negative bacteria. The reported MIC is often in the range of 100 to 1,000 ?g/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. Major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plant antimicrobials against this group of microorganisms puzzling. Gram-negative bacteria have an effective permeability barrier, comprised of the outer membrane, which restricts the penetration of amphipathic compounds, and multidrug resistance pumps (MDRs), which extrude toxins across this barrier. It is possible that the apparent ineffectiveness of plant antimicrobials is largely due to the permeability barrier. We tested this hypothesis in the present study by applying a combination of MDR mutants and MDR inhibitors. A panel of plant antimicrobials was tested by using a set of bacteria representing the main groups of plant pathogens. The human pathogens Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhimurium were also tested. The results show that the activities of the majority of plant antimicrobials were considerably greater against the gram-positive bacteria Staphylococcus aureus and Bacillus megaterium and that disabling of the MDRs in gram-negative species leads to a striking increase in antimicrobial activity. Thus, the activity of rhein, the principal antimicrobial from rhubarb, was potentiated 100- to 2,000-fold (depending on the bacterial species) by disabling the MDRs. Comparable potentiation of activity was observed with plumbagin, resveratrol, gossypol, coumestrol, and berberine. Direct measurement of the uptake of berberine, a model plant antimicrobial, confirmed that disabling of the MDRs strongly increases the level of penetration of berberine into the cells of gram-negative bacteria. These results suggest that plants might have developed means of delivering their antimicrobials into bacterial cells. These findings also suggest that plant antimicrobials might be developed into effective, broad-spectrum antibiotics in combination with inhibitors of MDRs.
Tegos, George; Stermitz, Frank R.; Lomovskaya, Olga; Lewis, Kim
Controlling the release of peptide antimicrobial agents from surfaces.
Medical conditions are often exacerbated by the onset of infection caused by hospital dwelling bacteria such as Staphylococcus aureus. Antibiotics taken orally or intravenously can require large and frequent doses, further contributing to the sharp rise in resistant bacteria observed over the past several decades. These existing antibiotics are also often ineffective in preventing biofilm formation, a common cause of medical device failure. Local delivery of new therapeutic agents that do not allow bacterial resistance to occur, such as antimicrobial peptides, could alleviate many of the problems associated with current antibacterial treatments. By taking advantage of the versatility of layer-by-layer assembly of polymer thin films, ponericin G1, an antimicrobial peptide known to be highly active against S. aureus, was incorporated into a hydrolytically degradable polyelectrolyte multilayer film. Several film architectures were examined to obtain various drug loadings that ranged from 20 to 150 microg/cm2. Release was observed over approximately ten days, with varying release profiles, including burst as well as linear release. Results indicated that film-released peptide did not suffer any loss in activity against S. aureus and was able to inhibit bacteria attachment, a necessary step in preventing biofilm formation. Additionally, all films were found to be biocompatible with the relevant wound healing cells, NIH 3T3 fibroblasts and human umbilical vein endothelial cells. These films provide the level of control over drug loading and release kinetics required in medically relevant applications including coatings for implant materials and bandages, while eliminating susceptibility to bacterial resistance. PMID:20004967
Shukla, Anita; Fleming, Kathleen E; Chuang, Helen F; Chau, Tanguy M; Loose, Christopher R; Stephanopoulos, Gregory N; Hammond, Paula T
Cough Illness\\/Bronchitis—Principles of Judicious Use of Antimicrobial Agents
Millions of courses of antibiotics are pre- scribed for children with acute cough illness each year, despite evidence from randomized, placebo-controlled trials that such treatment is not effective. Evidence that children with cough for <10 days should not be treated with antimicrobial agents is presented. Older children with prolonged cough or those with underlying lung disease may benefit from antimicrobial
Katherine L. O'Brien; Scott F. Dowell; Benjamin Schwartz; S. Michael Marcy; William R. Phillips; Michael A. Gerber
Susceptibilities of Corynebacterium bovis and Corynebacterium amylocolatum Isolates from Bovine Mammary Glands to 15 Antimicrobial Agents
Coryneform bacteria are frequently isolated from bovine mastitis and are associated with economic losses. Generally, the MICs of the 15 antimicrobial agents tested at which 90% of the isolates tested are inhibited for 46 Corynebacterium bovis and 13 Corynebacterium amylocolatum strains were low. These are the first quantitative antimicrobial susceptibility data available for coryneforms from bovine mastitis. Data from this
Use of antimicrobial agents in veterinary medicine and food animal production
Antimicrobial resistance is a growing area of concern in both human and veterinary medicine. This review presents an overview of the use of antimicrobial agents in animals for therapeutic, metaphylactic, prophylactic and growth promotion purposes. In addition, factors favouring resistance development and transfer of resistance genes between different bacteria, as well as transfer of resistant bacteria between different hosts, are
S. Schwarz; C. Kehrenberg; T. R. Walsh
Association between the consumption of antimicrobial agents in animal husbandry and the occurrence of resistant bacteria among food animals
Antimicrobial agents are used in food animals for therapy and prophylaxis of bacterial infections and in feed to promote growth. The use of antimicrobial agents for food animals may cause problems in the therapy of infections by selecting for resistance among bacteria pathogenic for animals or humans. The emergence of resistant bacteria and resistance genes following the use of antimicrobial
Frank Mřller Aarestrup
In vitro susceptibility of Bacillus spp. to selected antimicrobial agents.
Although often dismissed as contaminants when isolated from blood cultures, Bacillus spp. are increasingly recognized as capable of causing serious systemic infections. As part of a clinical-microbiological study, 89 strains of Bacillus spp. isolated from clinical blood cultures between 1981 and 1985 had their species determined and were tested for antimicrobial agent susceptibility to 18 antibiotics. Species of isolates were determined by the API 50CH and API 20E systems. Bacillus cereus (54 strains) was the most common species isolated, followed by B. megaterium (13 strains), B. polymyxa (5 strains), B. pumilus (4 strains), B. subtilis (4 strains), B. circulans (3 strains), B. amyloliquefaciens (2 strains), B. licheniformis (1 strain), and Bacillus spp. (3 strains). Microdilution MIC susceptibility tests revealed all B. cereus strains to be susceptible to imipenem, vancomycin, chloramphenicol, gentamicin, and ciprofloxacin. Non-B. cereus strains were most susceptible to imipenem, vancomycin, LY146032, and ciprofloxacin. Disk susceptibility testing suggested that B. cereus was rarely susceptible to penicillins, semisynthetic penicillins, or cephalosporins with the exception of mezlocillin. In contrast, many non-B. cereus strains were susceptible to penicillins, semisynthetic penicillins, and cephalosporins, but marked variability was noted among species.
Weber, D J; Saviteer, S M; Rutala, W A; Thomann, C A
Antimicrobial agent resistance in mycobacteria: molecular genetic insights.
The primary theme emerging from molecular genetic work conducted with Mycobacterium tuberculosis and several other mycobacterial species is that resistance is commonly associated with simple nucleotide alterations in target chromosomal genes rather than with acquisition of new genetic elements encoding antibiotic-altering enzymes. Mutations in an 81-bp region of the gene (rpoB) encoding the beta subunit of RNA polymerase account for rifampin resistance in 96% of M. tuberculosis and many Mycobacterium leprae isolates. Streptomycin resistance in about one-half of M. tuberculosis isolates is associated with missense mutations in the rpsL gene coding for ribosomal protein S12 or nucleotide substitutions in the 16S rRNA gene (rrs). Mutations in the katG gene resulting in catalase-peroxidase amino acid alterations nad nucleotide substitutions in the presumed regulatory region of the inhA locus are repeatedly associated with isoniazid-resistant M. tuberculosis isolates. A majority of fluoroquinolone-resistant M. tuberculosis isolates have amino acid substitutions in a region of the DNA gyrase A subunit homologous to a conserved fluoroquinolone resistance-determining region. Multidrug-resistant isolates of M. tuberculosis arise as a consequence of sequential accumulation of mutations conferring resistance to single therapeutic agents. Molecular strategies show considerable promise for rapid detection of mutations associated with antimicrobial resistance. These approaches are now amenable to utilization in an appropriately equipped clinical microbiology laboratory.
Musser, J M
Comparative physiological disposition of two nitrofuran anti-microbial agents.
The physiological disposition of two nitrofuran derivatives used as antimicrobial agents for the treatment of acute infectious diarrhoea was evaluated in humans and animals. Upon administration of a single oral dose (600 mg) of nifurzide or nifuroxazide, no unchanged parent drug was detected in human blood or urine. In rats given 14C-nifurzide and 14C-nifuroxazide at a dose of 10 mg kg-1, 5 per cent and 17 per cent of the dose of nifurzide and nifuroxazide, respectively, were excreted in urine over a 48-hour period. None of this radioactivity was present as unchanged drug, indicating that renal excretion of both drugs occurs as metabolites. In the faeces 20 per cent of the radioactivity recovered was associated with unchanged nifuroxazide as compared with 100 per cent for nifurzide. Whole body autoradiography using rats showed that after oral administration of 14C-nifurzide and 14C-nifuroxazide, most of the radioactivity remained in the gastrointestinal lumen. PMID:3779034
Labaune, J P; Moreau, J P; Byrne, R
Lauryl-poly-L-lysine: A New Antimicrobial Agent?
The development of multiple antibiotic resistance is a global problem. It is necessary to find new tools whose mechanisms of action differ from those of currently used antibiotics. It is known that fatty acids and cationic polypeptides are able to fight bacteria. Here, we describe the synthesis of fatty acids linked to a polypeptide with antibacterial activity. The linkage of fatty acids to a polypeptide is reported to increase the antibacterial effect of the linked fatty acid in comparison with free fatty acids (FA) or free poly-L-lysine (PLL) or a mixture of both (FA free + PLL free). A number of C6–C18 fatty acids were linked to PLL to obtain new synthetic products. These compounds were assessed in vitro to evaluate their antibacterial activity. Some fatty acid-PLLs showed a good ability to fight bacteria. Their bactericidal activity was evaluated, and, lauryl linked to PLL was found to be the most active product against both Gram-positive and Gram-negative bacteria. This new active component showed a good degree of specificity and reproducibility and its minimum inhibitory concentration (MIC) was comparatively good. The antibacterial activity of the lauryl-PLL compound suggests that it is a new and promising antimicrobial agent.
Thuault, Veronique; Mangas, Arturo; Thienpont, Anne; Geffard, Michel
Photo induced silver on nano titanium dioxide as an enhanced antimicrobial agent for wool
In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO2 as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus
Majid Montazer; Amir Behzadnia; Esfandiar Pakdel; Mohammad Karim Rahimi; Mohammad Bameni Moghadam
Animals living in polluted environments are potential source of antimicrobials against infectious agents
The antimicrobials crisis is a ticking time bomb which could lead to millions of people dying from untreatable infections. With the worsening trends of antimicrobial resistance, we are heading towards a pre-antibiotic era. Thus, there is a need for newer and more powerful antibiotic agents. The search for new antibiotic compounds originating from natural resources is a promising research area. Animals living in germ-infested environments are a potent source of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of bacteria, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances which show potent activity in the nervous system. We hope that the discovery of antimicrobial activity in the cockroach brain will stimulate research in finding antimicrobials from unusual sources, and has potential for the development of novel antibiotics. Nevertheless, intensive research in the next few years will be required to approach or realize these expectations.
Lee, Simon; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed
Novel Hybrid-Type Antimicrobial Agents Targeting the Switch Region of Bacterial RNA Polymerase
The bacterial RNA polymerase (RNAP) is an ideal target for the development of antimicrobial agents against drug-resistant bacteria. Especially, the switch region within RNAP has been considered as an attractive binding site for drug discovery. Here, we designed and synthesized a series of novel hybrid-type inhibitors of bacterial RNAP. The antimicrobial activities were evaluated using a paper disk diffusion assay, and selected derivatives were tested to determine their MIC values. The hybrid-type antimicrobial agent 29 showed inhibitory activity against Escherichia coli RNAP. The molecular docking study suggested that the RNAP switch region would be the binding site of 29.
In vitro evaluation of the root canal cleaning ability of plant extracts and their antimicrobial action.
This in vitro study evaluated both the antimicrobial activity and the root canal cleaning ability of plant extracts used in irrigation solutions. The antimicrobial activities of the aroeira-da-praia (Schinus terebintifolius Raddi) and the quixabeira (Syderoxylum obtusifolium Roem & Schult) hydroalcoholic extracts, of 2.5% sodium hypochlorite (NaOCl) and of 0.12% chlorhexidine (positive control) against Enterococcus faecalis were tested with the agar well diffusion method. The level of root canal cleanliness was examined by scanning electron microscopy (SEM). Twenty one single-rooted human teeth were divided into three groups according to the irrigation solution applied: 1) 50% aroeira-da-praia; 2) 50% quixabeira and 3) a combination of 2.5% sodium hypochlorite + 17% EDTA. All solutions tested demonstrated antimicrobial activity against Enterococcus faecalis. The SEM analysis revealed that higher and lower degrees of surface cleaning were observed, in the three groups, respectively for the coronal and apical thirds, in that quixabeira showed the greatest efficiency in removing the smear layer in the apical third. All the agents tested presented antimicrobial activity against E. faecalis. None, however, was able to completely remove the smear layer of the dentinal surface in the different thirds of the root canal. The results suggest that the analyzed plant extracts may represent a new therapeutic option in the list of alternative agents available for endodontic treatment. PMID:22641440
Costa, Edja Maria Melo de Brito; Evangelista, Augusto Pierry de Araújo; Medeiros, Ana Cláudia Dantas de; Dametto, Fábio Roberto; Carvalho, Rejane Andrade de
Insect Antimicrobial Peptides as New Weapons Against Plant Pathogens
\\u000a One action to furnish the increasing demand for food and feed of the growing world population is to reduce yield losses caused\\u000a by plant diseases. Biotechnology helps to generate crop plants with improved resistance against pathogenic bacteria, fungi,\\u000a and pests. The expression of antimicrobial peptides (AMPs) from various sources is a promising approach to pursue strengthening\\u000a plant health in a
Carin Jansen; Karl-Heinz Kogel
The dynamic observation of plasma concentration of antimicrobial agents during balanced ultrafiltration in vitro.
Routine perioperative intravenous antimicrobial agents are administered as surgical prophylaxis. However, whether balanced ultrafiltration during extracorporeal circulation has substantial effect on the concentration of antimicrobial agents remains unclear. The concentrations of antimicrobial agents in plasma and ultrafiltrate samples were measured in this pseudo-extracorporeal circulation model. Extracorporeal circulation consisted of cardiotomy reservoir, membrane oxygenator, and pediatric arterial line filter. A hemoconcentrator was placed between the arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. Two kinds of antimicrobial agents, cefotiam (320?mg) and cefmetazole (160?mg), were bolus added into the circuit. After 30?min of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100?mm?Hg with a Hoffman clamp. The rate of ultrafiltration (12?mL/min) was controlled by ultrafiltrate outlet pressure. An identical volume of Plasmalyte A was dripped into the circuit to maintain stable hematocrit during 45?min of experiment. Plasma and ultrafiltrate samples were drawn every 5?min, and concentrations of antimicrobial agents (including cefotiam and cefmetazole) were measured with high performance liquid chromatography. Both antimicrobial agents were detected in ultrafiltrate, demonstrating hemoconcentration may remove antimicrobial agents. The concentrations of plasma antimicrobial agents decreased linearly with the increase of ultrafiltrate volume. At end of balanced ultrafiltration, the concentration of plasma cefotiam was 104.96?±?44.36?mg/L, which is about 44.38%?±?7.42% of the initial concentration (238.95?±?101.12?mg/L) (P?0.001); the concentration of plasma cefmetazole decreased linearly to 25.76?±?14.78?mg/L, which is about 49.69%?±?10.49% of the initial concentration (51.49?±?28.03?mg/L) (P?0.001). The total amount of cefotiam in ultrafiltrate is 27.16%?±?12.17% of the total dose administered, whereas cefmetazole in ultrafiltrate is 7.74%?±?4.17%. Balanced ultrafiltration may remove antimicrobial agents from plasma and has a prominent influence on plasma concentration of antimicrobial agent. The strategy of surgical prophylaxis should consider this unique technique during extracorporeal circulation. PMID:23865445
Fang, Yinghui; Guan, Yulong; Wan, Caihong; Fu, Zhida; Jiang, Juanjuan; Wu, Chunfu; Zhao, Ju; Sun, Peng; Long, Cun
Antimicrobial and phytochemical studies on 45 Indian medicinal plants against multi-drug resistant human pathogens
Ethanolic extracts of 45 Indian medicinal plants traditionally used in medicine were studied for their antimicrobial activity against certain drug-resistant bacteria and a yeast Candida albicans of clinical origin. Of these, 40 plant extracts showed varied levels of antimicrobial activity against one or more test bacteria. Anticandidal activity was detected in 24 plant extracts. Overall, broad-spectrum antimicrobial activity was observed
Iqbal Ahmad; Arina Z. Beg
In vitro susceptibility of bovine digital dermatitis associated spirochaetes to antimicrobial agents
Bovine digital dermatitis (BDD) is an infectious lameness in cattle, which has a large global impact in terms of animal welfare and cost. The majority of evidence suggests that spirochaetes are the aetiological agent of this disease. The aim of this study was to identify the susceptibility of BDD associated spirochaetes to a range of antimicrobial agents with a view
Nicholas J. Evans; Jennifer M. Brown; Ibrahim Demirkan; Richard Birtles; C. Anthony Hart; Stuart D. Carter
Bacterial resistance to antimicrobial agents used in fish farming: A critical evaluation of method and meaning
The use of antimicrobial agents in aquaculture has resulted in the increase in the frequency of strains resistant to these agents. Potentially these resistant strains can have an impact on the therapy of fish diseases, the therapy of human diseases or the environment of the fish farms. The analysis of the extent of these impacts is hindered by the limited
Peter Smith; Maura Hiney; Ole Samuelsen
Antimicrobial activity of some plant extracts having hepatoprotective effects
The antimicrobial activity of hot water and ethanolic extracts of six plant extracts, utilized in Pakistan for the cure of liver damage, were studied. The extracts of Acacia arabica, Nymphaea lotus, Sphareranthus hirtus, Emblica officinalis, Cinchorium intybus and Cardus marianum were tested in vitro against seven bacterial species and two fungal species by well-diffusion method and micro- dilution methods. The
Ammara Hassan; Salma Rahman; Farah Deeba; Shahid Mahmud
Antimicrobial activity of some medicinal plants of the Cerrado, Brazil.
In order to determine the potential of Cerrado plants as sources of antimicrobial activity, the phytochemical screening of ethanol extracts from Virola surinamensis, Qualea grandiflora, Alchornea castaneifolia, Hancornia speciosa and Curatella americana traditionally used in folk medicine are reported. PMID:18350520
Costa, E S; Hiruma-Lima, C A; Lima, E O; Sucupira, G C; Bertolin, A O; Lolis, S F; Andrade, F D P; Vilegas, W; Souza-Brito, A R M
Screening of some Cuban medicinal plants for antimicrobial activity
The antimicrobial activities of 23 extracts of 12 Cuban plant species reported in traditional medicine were tested. The agar diffusion method was used to assess the activity against four bacteria and one yeast: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The results, evaluated as the diameter of the inhibition zone of microbial growth, showed that nine
M. J. Martínez; J. Betancourt; N. Alonso-González; A. Jauregui
High-Level Antimicrobial Efficacy of Representative Mediterranean Natural Plant Extracts against Oral Microorganisms
Nature is an unexplored reservoir of novel phytopharmaceuticals. Since biofilm-related oral diseases often correlate with antibiotic resistance, plant-derived antimicrobial agents could enhance existing treatment options. Therefore, the rationale of the present report was to examine the antimicrobial impact of Mediterranean natural extracts on oral microorganisms. Five different extracts from Olea europaea, mastic gum, and Inula viscosa were tested against ten bacteria and one Candida albicans strain. The extraction protocols were conducted according to established experimental procedures. Two antimicrobial assays—the minimum inhibitory concentration (MIC) assay and the minimum bactericidal concentration (MBC) assay—were applied. The screened extracts were found to be active against each of the tested microorganisms. O. europaea presented MIC and MBC ranges of 0.07–10.00?mg?mL?1 and 0.60–10.00?mg?mL?1, respectively. The mean MBC values for mastic gum and I. viscosa were 0.07–10.00?mg?mL?1 and 0.15–10.00?mg?mL?1, respectively. Extracts were less effective against C. albicans and exerted bactericidal effects at a concentration range of 0.07–5.00?mg?mL?1 on strict anaerobic bacteria (Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Parvimonas micra). Ethyl acetate I. viscosa extract and total mastic extract showed considerable antimicrobial activity against oral microorganisms and could therefore be considered as alternative natural anti-infectious agents.
Cecere, Manuel; Skaltsounis, Alexios Leandros; Argyropoulou, Aikaterini; Hellwig, Elmar; Aligiannis, Nektarios
Tolerance of Staphylococcus epidermidis grown from indwelling vascular catheters to antimicrobial agents
During a prospective study of indwelling vascular catheter-related infections, 134 isolates ofStaphylococcus epidermidis were grown from 700 catheter tips.In vitro antimicrobial susceptibility testing of these isolates to oxacillin, vancomycin and ofloxacin was performed using the standard broth microdilution technique. These results were compared to those for the same organisms grown in biofilm before the addition of antimicrobial agents. In 96-well
N Khardori; M Yassien; K Wilson
Intravascular catheters impregnated with antimicrobial agents: a milestone in the prevention of bloodstream infections
Vascular catheters impregnated with antimicrobial agents have been shown to decrease the risk of catheter-related colonization\\u000a and bloodstream infections. Various antimicrobials and antiseptics have been used. In a recent meta-analysis of 12 studies,\\u000a catheters coated with chlorhexidine and silver sulfadiazine (CH\\/SS) were shown to be significantly less likely to be associated\\u000a with catheter-related bloodstream infections than uncoated catheters. However, these
Issam Raad; Hend Hanna
Occurrence of Salmonella spp. in broiler chicken carcasses and their susceptibility to antimicrobial agents
The present study was carried out to evaluate the occurrence of Salmonellae in broiler chicken carcasses and to determine the antimicrobial resistance profile of the isolated strains. Twenty-five out of the 260 broiler chicken carcasses samples (9.6%) were positive for Salmonella. S. Enteritidis was the most frequent serovar. Nineteen Salmonella isolates were tested for antimicrobial resistance, and the results indicated that 94.7% were resistant to at least one antimicrobial agent. Resistance to streptomycin (73.7%), nitrofurantoin (52.3%), tetracycline (31.6%), and nalidixic acid (21%) were the prevalent amongst Salmonella strains tested.
Duarte, Dalila Angelica Moliterno; Ribeiro, Aldemir Reginato; Vasconcelos, Ana Mercia Mendes; Santos, Sylnei Barros; Silva, Juliana Vital Domingos; de Andrade, Patricia Lucia Arruda; de Arruda Falcao, Lucia Sadae Pereira da Costa
Isolation and Characterization of Antimicrobial Compounds in Plant Extracts against Multidrug-Resistant Acinetobacter baumannii
The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii.
Miyasaki, Yoko; Rabenstein, John D.; Rhea, Joshua; Crouch, Marie-Laure; Mocek, Ulla M.; Kittell, Patricia Emmett; Morgan, Margie A.; Nichols, Wesley Stephen; Van Benschoten, M. M.; Hardy, William David; Liu, George Y.
Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine
Fifty medicinal plants belonging to 26 families were studied for their antimicrobial activity. Among 50 plants tested, 72% showed antimicrobial activity. About 22 plant extracts from 15 families exhibited activity against both Gram-positive and Gram-negative bacteria. Fourteen plants belonging to 11 families did not show activity against any of the bacteria tested. Only nine plant extracts showed antifungal activity. The
D. Srinivasan; Sangeetha Nathan; T. Suresh; P. Lakshmana Perumalsamy
Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance.
There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema. PMID:17291738
Weckesser, S; Engel, K; Simon-Haarhaus, B; Wittmer, A; Pelz, K; Schempp, C M
In vitro synergistic activity between bismuth subcitrate and various antimicrobial agents against Campylobacter pyloridis (C. pylori).
The in vitro interactions between bismuth subcitrate and a variety of antimicrobial agents against 12 Campylobacter pyloridis (C. pylori) isolates were studied by the agar dilution checkerboard technique. The combination of bismuth subcitrate with the older quinolone, oxolinic acid, produced synergistic activity against all strains. This observation, however, could not be extended to the (aryl) fluoroquinolones, norfloxacin, ofloxacin, and difloxacin, since synergy was rare or absent when bismuth subcitrate was combined with these antibiotics. Among the other antimicrobial agents tested, rifampin and the beta-lactams frequently showed showed MICs for C. pyloridis similar to those of bismuth subcitrate.
Van Caekenberghe, D L; Breyssens, J
In vitro susceptibility of Alcaligenes denitrificans subsp. xylosoxidans to 24 antimicrobial agents.
The in vitro susceptibilities of 37 clinical isolates of Alcaligenes denitrificans subsp. xylosoxidans to 24 antimicrobial agents were determined. Imipenem was the only drug with consistent activity (MIC for 90% of isolates, 2 micrograms/ml). Piperacillin, ticarcillin-clavulanic acid, ceftazidime, and co-trimoxazole were active against most strains. All the isolates were resistant to ampicillin, cefazolin, cefuroxime, cefamandole, cefotetan, ceftriaxone, cefotaxime, aztreonam, amdinocillin, and temocillin. Most isolates were resistant to the aminoglycosides tested, including amikacin. Lack of activity was also observed for all new 4-quinolone antimicrobial agents.
Glupczynski, Y; Hansen, W; Freney, J; Yourassowsky, E
Evaluation of three medicinal plants for anti-microbial activity.
Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order - Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria. PMID:23723653
Pratap, Gowd M J S; Manoj, Kumar M G; Sai, Shankar A J; Sujatha, B; Sreedevi, E
Evaluation of three medicinal plants for anti-microbial activity
Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order – Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria.
Pratap, Gowd M. J. S; Manoj, Kumar M. G.; Sai, Shankar A. J.; Sujatha, B.; Sreedevi, E.
[Recommendations for selecting antimicrobial agents for in vitro susceptibility studies using automatic and semiautomatic systems].
The number of clinical microbiology laboratories that have incorporated automatic susceptibility testing devices has increased in recent years. The majority of these systems determine MIC values using microdilution panels or specific cards, with grouping into clinical categories (susceptible, intermediate or resistant) and incorporate expert systems to infer resistance mechanisms. This document presents the recommendations of a group of experts designated by Grupo de Estudio de los Mecanismos de Acción y Resistencia a los Antimicrobianos (GEMARA, Study group on mechanisms of action and resistance to antimicrobial agents) and Mesa Espańola de Normalización de la Sensibilidad y Resistencia a los Antimicrobianos (MENSURA, Spanish Group for Normalizing Antimicrobial Susceptibility and Antimicrobial Resistance), with the aim of including antimicrobial agents and selecting concentrations for the susceptibility testing panels of automatic systems. The following have been defined: various antimicrobial categories (A: must be included in the study panel; B: inclusion is recommended; and C: inclusion is secondary, but may facilitate interpretative reading of the antibiogram) and groups (0: not used in therapeutics but may facilitate the detection of resistance mechanisms; 1: must be studied and always reported; 2: must be studied and selectively reported; 3: must be studied and reported at a second level; and 4: should be studied in urinary tract pathogens isolated in urine and other specimens). Recommended antimicrobial concentrations are adapted from the breakpoints established by EUCAST, CLSI and MENSURA. This approach will lead to more accurate susceptibility testing results with better detection of resistance mechanisms, and allowing to reach the clinical goal of the antibiogram. PMID:17583653
Cantón, Rafael; Alós, Juan Ignacio; Baquero, Fernando; Calvo, Jorge; Campos, José; Castillo, Javier; Cercenado, Emilia; Domínguez, M Angeles; Lińares, Josefina; López-Cerezo, Lorena; Marco, Francesc; Mirelis, Beatriz; Morosini, María-Isabel; Navarro, Ferran; Oliver, Antonio; Pérez-Trallero, Emilio; Torres, Carmen; Martínez-Martínez, Luis
Minimum inhibitory concentrations for selected antimicrobial agents against Fusobacterium necrophorum isolated from hepatic abscesses in cattle and sheep.
Minimum inhibitory concentrations for 35 antimicrobial agents against 100 Fusobacterium necrophorum isolates from hepatic abscesses in sheep and cattle were determined. Twelve of the thirteen beta-lactam antibiotics tested inhibited growth of 100% of strains tested. Of the remaining antimicrobial agents, extensive susceptibility was found for: spiramycin, josamycin, lincomycin, tylosin, oxytetracycline, chlortetracycline, rufloxacin, metronidazole, cotrimoxazole, sulfadimethoxine, virginiamycin and fosfomycin. PMID:9049945
Mateos, E; Piriz, S; Valle, J; Hurtado, M; Vadillo, S
Expression and functional characterization of the plant antimicrobial snakin-1 and defensin recombinant proteins.
In this study, for the first time, functionally active, recombinant, cysteine-rich plant proteins snakin-1 (SN1) and defensin (PTH1) were expressed and purified using a prokaryotic expression system. The overall level of antimicrobial activities of SN1 and PTH1 produced in Escherichia coli was commensurate with that of the same proteins previously obtained from plant tissues. Both proteins exhibited strong antibacterial activity against the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus (50% inhibitory concentration (IC(50)) 1.5-8 microM) and antifungal activity against the phytopathogenic fungi Colletotrichum coccoides and Botrytis cinerea (IC(50) 5-14 microM). Significantly weaker activity was observed against Pseudomonas syringae pv. syringae and Pseudomonas syringae pv. tabaci. A pronounced synergistic antimicrobial effect against P. syringae pv. syringae and an additive effect against P. syringae pv. tabaci occurred with a combination of SN1 and PTH1. Aggregation of C. michiganensis subsp. sepedonicus bacterial cells at all protein concentrations tested was observed with the combination of SN1 and PTH1 and with SN1 alone. Our results demonstrate the use of a cost effective prokaryotic expression system for generation and in vitro characterization of plant cysteine-rich proteins with potential antimicrobial activities against a wide range of phytopathogenic microorganisms in order to select the most effective agents for future in vivo studies. PMID:18824107
Kovalskaya, Natalia; Hammond, Rosemarie W
Synthesis of new macrocyclic polyamides as antimicrobial agent candidates.
A series of macrocyclic imides and Schiff-bases have been prepared via the cyclocondensation of pyridine-2,6-dicarbonyl dichloride (1) with L-ornithine methyl ester to give the corresponding macrocyclic bisester 2. Treatment of 2 with hydrazine hydrate gave macrocyclic bisacid hydrazide 3, which was used as starting material. Condensation of bishydrazide 3 with diacid anhydrides or aromatic aldehydes in refluxing acetic acid or ethanol gave the corresponding macrocyclic bisimides 4, 5a,b and macrocyclic bis- hydrazones 6a-j, respectively. The structure assignments of the new compounds were based on chemical and spectroscopic evidence. The antimicrobial screening showed that many of these newly synthesized compounds have good antimicrobial activities, comparable to ampicillin and ketaconazole used as reference drugs. PMID:23222868
El-Salam, Osama I Abd; Al-Omar, Mohamed A; Fayed, Ahmed A; Flefel, Eman M; Amr, Abd El-Galil E
Pectin functionalized with natural fatty acids as antimicrobial agent.
Several pectin derivatives were prepared by chemical modifications of the polysaccharide with natural fatty acids. The obtained biodegradable pectin-based materials, pectin-linoleate, pectin-oleate and pectin-palmitate, were investigated for their antimicrobial activity against several bacterial strains, Staphylococcus aureus and Escherichia coli. Good results were obtained for pectin-oleate and pectin-linoleate, which inhibit the growth of the selected microorganisms by 50-70%. They exert the better antimicrobial activity against S. aureus. Subsequently, the pectin-oleate and the pectin-linoleate samples were coated on polyethylene films and were assessed for their capacity to capture the oxygen molecules, reducing its penetration into the polymeric support. These results confirmed a possible application of the new materials in the field of active food packaging. PMID:24751510
Calce, Enrica; Mignogna, Eleonora; Bugatti, Valeria; Galdiero, Massimiliano; Vittoria, Vittoria; De Luca, Stefania
The potential of nitric oxide releasing therapies as antimicrobial agents
Nitric oxide (NO) is a short-lived, diatomic, lipophilic gas that plays an integral role in defending against pathogens. Among its many functions are involvement in immune cell signaling and in the biochemical reactions by which immune cells defend against bacteria, fungi, viruses and parasites. NO signaling directs a broad spectrum of processes, including the differentiation, proliferation, and apoptosis of immune cells. When secreted by activated immune cells, NO diffuses across cellular membranes and exacts nitrosative and oxidative damage on invading pathogens. These observations led to the development of NO delivery systems that can harness the antimicrobial properties of this evanescent gas. The innate microbicidal properties of NO, as well as the antimicrobial activity of the various NO delivery systems, are reviewed.
Schairer, David O.; Chouake, Jason S.; Nosanchuk, Joshua D.; Friedman, Adam J.
Antimicrobial properties of some plant extracts against bacteria.
Plant extracts obtained from Feronia limonia (leaves) Xanthium strumarium (flowering twigs) and Glossocardia bosvellia (leaves) were tested for their antimicrobial properties against certain bacterial species. Feronia leaf extract was ineffective on Bacillus pumilus and X. campestris, Vibrio cholerae was found quite sensitive to this extract. The extract of X. strumarium showed an abnormality with V. cholerae, where the inhibition exceeded the control with established antibiotics. Similarly, G. bosvellia caused maximum inhibition in Bacillus mycoides. PMID:6667916
Mehta, P; Chopra, S; Mehta, A
Protein C Inhibitor--A Novel Antimicrobial Agent
Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which subsequently leads to their permeabilization. As shown by negative staining electron microscopy, treatment of Escherichia coli or Streptococcus pyogenes bacteria with PCI triggers membrane disruption followed by the efflux of bacterial cytosolic contents and bacterial killing. The antimicrobial activity of PCI is located to the heparin-binding site of the protein and a peptide spanning this region was found to mimic the antimicrobial activity of PCI, without causing lysis or membrane destruction of eukaryotic cells. Finally, we show that platelets can assemble PCI on their surface upon activation. As platelets are recruited to the site of a bacterial infection, these results may explain our finding that PCI levels are increased in tissue biopsies from patients suffering from necrotizing fasciitis caused by S. pyogenes. Taken together, our data describe a new function for PCI in innate immunity.
Malmstrom, Erik; Morgelin, Matthias; Malmsten, Martin; Johansson, Linda; Norrby-Teglund, Anna; Shannon, Oonagh; Schmidtchen, Artur; Meijers, Joost C. M.; Herwald, Heiko
Chitosan-thioglycolic acid as a versatile antimicrobial agent.
As functionalized chitosans hold great potential for the development of effective and broad-spectrum antibiotics, representative chitosan derivatives were tested for antimicrobial activity in neutral media: trimethyl chitosan (TMC), carboxy-methyl chitosan (CMC), and chitosan-thioglycolic acid (TGA; medium molecular weight: MMW-TGA; low molecular weight: LMW-TGA). Colony forming assays indicated that LMW-TGA displayed superior antimicrobial activity over the other derivatives tested: a 30 min incubation killed 100% Streptococcus sobrinus (Gram-positive bacteria) and reduced colony counts by 99.99% in Neisseria subflava (Gram-negative bacteria) and 99.97% in Candida albicans (fungi). To elucidate LMW-TGA effects at the cellular level, microscopic studies were performed. Use of fluorescein isothiocyanate (FITC)-labeled chitosan derivates in confocal microscopy showed that LMW-TGA attaches to microbial cell walls, while transmission electron microscopy indicated that this derivative severely affects cell wall integrity and intracellular ultrastructure in all species tested. We therefore propose LMW-TGA as a promising and effective broad-band antimicrobial compound. PMID:23470196
Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Käch, Andres; Maake, Caroline; Patzke, Greta R
Screening of some indigenous Qatari medicinal plants for antimicrobial activity.
Aqueous, ethanol and butanol crude extracts of the aerial parts of ten plants exhibited variable degrees of antimicrobial activity against four bacterial and two fungal species. Aqueous extracts had low antimicrobial activity against E.coli, P.aeruginosa, B. cerreus, S.aureus, C.albicans and A.flavus. Avicennia marina (AM) aqueous extract exhibited a moderate antifungal activity. Ethanol and butanol crude extracts exhibited an improved antimicrobial activity. However, butanol exhibited a superior antimicrobial activity compared with aqueous and ethanol crudes. Compared with the standard antibiotics tested the butanol extract had the highest activity. Butanol extracts at 2000 microg/disc of AM, Lotus halophilus (LA), Pulicaria gnaphaloides (PG) and Capparis spinosa (CS) had a very good antibacterial activity against both gram-positive and -negative bacteria as well as moderate to good antifungal activity against C. albicans and A. flavus. Medicago laciniata (ML), Limonium axillare (LA) and (PG) butanol crude extract compared with standard chloramphenicol, tetracycline and nalidixic acid exhibited a superior antifungal activity. PMID:12458480
Mahasneh, Adel M
Mutant prevention concentration and mutant selection window for 10 antimicrobial agents against Rhodococcus equi.
The objectives of this study were to determine the mutant prevention concentration (MPC), time above the MPC and mutant selection window for 10 antimicrobial agents against Rhodococcus equi and to determine if the combination of a macrolide with rifampin would decrease emergence of resistant mutants. Antimicrobial agents investigated (erythromycin, clarithromycin, azithromycin, rifampin, amikacin, gentamicin, enrofloxacin, vancomycin, imipenem, and doxycycline) were selected based on in vitro activity and frequency of use in foals or people infected with R. equi. Each antimicrobial agent or combination of agents was evaluated against four virulent strains of R. equi. MPC were determined using an agar plate assay. Pharmacodynamic parameters were calculated using published plasma and pulmonary pharmacokinetic variables. There was a significant (P<0.001) effect of the type of antimicrobial agent on the MPC. The MPC of clarithromycin (1.0 ?g/ml) was significantly lower and the MPC of rifampin and amikacin (512 and 384 ?g/ml, respectively) were significantly higher than that of all other antimicrobial agents tested. Combining erythromycin, clarithromycin, or azithromycin with rifampin resulted in a significant (P?0.005) decrease in MPC and MPC/MIC ratio. When MIC and MPC were combined with pharmacokinetic variables, only gentamicin and vancomycin were predicted to achieve plasma concentrations above the MPC for any given periods of time. Only clarithromycin and the combination clarithromycin-rifampin were predicted to achieve concentrations in bronchoalveolar cells and pulmonary epithelial lining fluid above the MPC for the entire dosing interval. In conclusion, the combination of a macrolide with rifampin considerably decreases the emergence of resistant mutants of R. equi. PMID:23915992
Berghaus, Londa J; Gigučre, Steeve; Guldbech, Kristen
Antidiabetic Agents from Medicinal Plants
Currently available therapeutic options for non-insulin-dependent diabetes mellitus, such as dietary modification, oral hypoglycemics, and insulin, have limitations of their own. Many natural products and herbal medicines have been recommended for the treatment of diabetes. The present paper reviews medicinal plants that have shown experimental or clinical antidiabetic activity and that have been used in traditional systems of medicine; the
Mankil Jung; Hyun Chul Lee; Yoon-Ho Kang; Eun Seok Kang; Sang Ki Kim
Use of Computer-Assisted Instruction to Review Microbiology and Antimicrobial Agents.
ERIC Educational Resources Information Center
A study assessed the effectiveness of a microcomputer-assisted instructional program using graphics, color, and text in simulations to enhance pharmacy students' knowledge of microbiology and antimicrobial agents. Results indicated high short- and long-term retention of information presented and higher levels of knowledge and comprehension among…
Carver, Peggy L.; And Others
This paper summarizes various mechanisms of microbiologic ally influenced corrosion (MIC) in municipal wastewater applications as it relates to steel, ductile iron, and reinforced concrete substrates. A novel method of using a 100% solids polyurethane coating system incorporated with anti-microbial agents is presented and its synergistic benefits are discussed.
Shiwei Guan
The therapeutic efficiency of 16 anti-microbial agents (Ethopabate, Nicarbazin, Sulphaquinoxaline, Furaltadone, Enterolyte-N, Sulphamethazine, Trinamide, Amprol, Phenamidine, Zoaquin, Halofuginone, Salinomycin, Monensin, Emtryl, Arprinocid and Amprolium) were examined against Cryptosporidium infections in mice. The Cryptosporidium was originally isolated from a field outbreak of calf diarrhoea. The drugs neither prevented nor modified the course of the infection as compared with infected, untreated mice.
Saul R Tzipori; Iris Campbell; Kenneth W Angus
Antimicrobial Activity of Some Essential Oils Against Paenibacillus larvae, the Causal Agent of American Foulbrood Disease
Essential oils from savory (Satureja hortensis), lavandin (Lavandula hybrida), eucalyptus (Eucalyptus globulus), lemon grass (Cymbopogon citratus), peppermint (Mentha × piperita), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis), and thyme (Thymus vulgaris) were tested for antimicrobial activities against Paenibacillus larvae, the causal agent of American Foulbrood Disease (AFB) of honey bees. Trials for determining the minimum inhibitory concentration (MIC) of these oils
Adriana M. Alippi; Jorge A. Ringuelet; Elsa L. Cerimele; María S. Re; Cynthia P. Henning
Helicobacter pylori infection in a pediatric population: in vitro susceptibilities to omeprazole and eight antimicrobial agents.
The in vitro activities of omeprazole and eight antimicrobial agents against 18 clinical strains of Helicobacter pylori isolated from a pediatric population were determined by an agar dilution method. Ampicillin and erythromycin were the most active agents in vitro. All strains were susceptible to azithromycin, ciprofloxacin, doxycycline, metronidazole, and tinidazole. One isolate demonstrated resistance to cefixime (MIC, greater than or equal to 4 micrograms/ml). H. pylori was inhibited by the proton pump inhibitor omeprazole.
Loo, V G; Sherman, P; Matlow, A G
Novel natural food antimicrobials.
Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry. PMID:22385168
Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe
Amphiphilic cationic ?(3R3)-peptides: membrane active peptidomimetics and their potential as antimicrobial agents.
We introduce a novel class of membrane active peptidomimetics, the amphiphilic cationic ?(3R3)-peptides, and evaluate their potential as antimicrobial agents. The design criteria, the building block and oligomer synthesis as well as a detailed structure-activity relationship (SAR) study are reported. Specifically, infrared reflection absorption spectroscopy (IRRAS) was employed to investigate structural features of amphiphilic cationic ?(3R3)-peptide sequences at the hydrophobic/hydrophilic air/liquid interface. Furthermore, Langmuir monolayers of anionic and zwitterionic phospholipids have been used to model the interactions of amphiphilic cationic ?(3R3)-peptides with prokaryotic and eukaryotic cellular membranes in order to predict their membrane selectivity and elucidate their mechanism of action. Lastly, antimicrobial activity was tested against Gram-positive M. luteus and S. aureus as well as against Gram-negative E. coli and P. aeruginosa bacteria along with testing hemolytic activity and cytotoxicity. We found that amphiphilic cationic ?(3R3)-peptide sequences combine high and selective antimicrobial activity with exceptionally low cytotoxicity in comparison to values reported in the literature. Overall, this study provides further insights into the SAR of antimicrobial peptides and peptidomimetics and indicates that amphiphilic cationic ?(3R3)-peptides are strong candidates for further development as antimicrobial agents with high therapeutic index. PMID:24694059
Mosca, Simone; Keller, Janos; Azzouz, Nahid; Wagner, Stefanie; Titz, Alexander; Seeberger, Peter H; Brezesinski, Gerald; Hartmann, Laura
Animals living in polluted environments are potential source of antimicrobials against infectious agents.
The antimicrobials crisis is a ticking time bomb which could lead to millions of people dying from untreatable infections. With the worsening trends of antimicrobial resistance, we are heading towards a pre-antibiotic era. Thus, there is a need for newer and more powerful antibiotic agents. The search for new antibiotic compounds originating from natural resources is a promising research area. Animals living in germ-infested environments are a potent source of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of bacteria, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances which show potent activity in the nervous system. We hope that the discovery of antimicrobial activity in the cockroach brain will stimulate research in finding antimicrobials from unusual sources, and has potential for the development of novel antibiotics. Nevertheless, intensive research in the next few years will be required to approach or realize these expectations. PMID:23265422
Lee, Simon; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed
Lycopersicon esculentum seeds: an industrial byproduct as an antimicrobial agent.
Lycopersicon esculentum (tomato) fruit is a widely studied matrix. However, only few works focus their attention on its seeds, which constitute a major byproduct of the tomato processing industry. In this study the antimicrobial potential of ten different tomato seed extracts from "Bull's heart" and "Cherry" varieties were analyzed against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and Gram-negative (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) bacteria and fungi (Candida albicans, Aspergillus fumigatus and Trichophyton rubrum). Regarding antibacterial capacity, the different extracts were revealed to be active only against Gram-positive bacteria, E. faecalis being the most susceptible one (MIC: 2.5-10 mg/mL). Concerning antifungal activity, "Bull's heart" extracts were the most active. In a general way C. albicans was the most susceptible species (MIC: 5-10 mg/mL). The chemical composition of the extracts was also pursued, concerning organic acids, phenolics and fatty acids, in order to establish a possible relationship with the observed antimicrobial effect. PMID:20707344
Taveira, Marcos; Silva, Luís R; Vale-Silva, Luís A; Pinto, Eugénia; Valentăo, Patrícia; Ferreres, Federico; Guedes de Pinho, Paula; Andrade, Paula B
Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil
Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations.
Violante, Ivana Maria Povoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues
Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil.
Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations. PMID:24031956
Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues
Modified lysozymes as novel broad spectrum natural antimicrobial agents in foods.
In recent years much attention and interest have been directed toward application of natural antimicrobial agents in foods. Some naturally occurring proteins such as lactoperoxidase, lactoferrin, and lysozyme have received considerable attention and are being considered as potential antimicrobial agents in foods. Lysozyme kills bacteria by hydrolyzing the peptidoglycan layer of the cell wall of certain bacterial species, hence its application as a natural antimicrobial agent has been suggested. However, limitations in the action of lysozyme against only Gram-positive bacteria have prompted scientists to extend the antimicrobial effects of lysozyme by several types of chemical modifications. During the last 2 decades extensive research has been directed toward modification of lysozyme in order to improve its antimicrobial properties. This review will report on the latest information available on lysozyme modifications and examine the applicability of the modified lysozymes in controlling growth of Gram-positive and Gram-negative bacteria in foods. The results of modifications of lysozyme using its conjugation with different small molecule, polysaccharides, as well as modifications using proteolytic enzymes will be reviewed. These types of modifications have not only increased the functional properties of lysozyme (such as solubility and heat stability) but also extended the antimicrobial activity of lysozyme. Many examples will be given to show that modification can decrease the count of Gram-negative bacteria in bacterial culture and in foods by as much as 5 log CFU/mL and in some cases essentially eliminated Escherichia coli. In conclusion this review demonstrates that modified lysozymes are excellent natural food preservatives, which can be used in food industry. PMID:24837015
Aminlari, Ladan; Mohammadi Hashemi, Marjan; Aminlari, Mahmoud
Antimicrobial and antioxidant activities of some Nigerian medicinal plants.
Ten Nigerian plants suggested from their ethnomedical uses to possess antimicrobial and antioxidant activities were studied for their anti-microbial and anti-oxidant properties. Antimicrobial activity was tested against Escherichia coli NCTC 10418, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Candida pseudotropicalis and Trichophyton rubrum (clinical isolate). Trichilia heudelotti leaf extract showed both antibacterial and antifungal activities and was the most active against all the strains of bacteria tested. Boerhavia diffusa, Markhamia tomentosa and T. heudelotti leaf extracts inhibited the gram negative bacteria E. coli and P. aeruginosa strains whereas those of M. tomentosa, T. heudelotti and Sphenoceutrum jollyamum root inhibited at least one of the fungi tested. At a concentration of 312 microg/ml, hexane and chloroform fractions of T. heudelotti extract inhibited 6 and 14% of the fifty multi-drug resistant bacteria isolates from clinical infections, respectively. At < or = 5 mg/ml, the CHCl(3) (64%) and aqueous (22%) fractions of T. heudelotti and those of CHCl(3) (34%) and EtOAC (48%) of M. tomentosa gave the highest inhibition that was stronger than their corresponding methanol extracts. The corresponding EC(50) of the extracts on M. acuminata, T. heudelotti, E. senegalensis and M. tomentosa were 4.00, 6.50, 13.33, and 16.50 ig/ml using the TLC staining and 1,1-dipheyl-2-picry-hydrazyl (DPPH) free radical scavenging assay. Therefore, leaf extracts of M. tomentosa and T. heudelotti, especially the latter, possess strong antimicrobial and antioxidant activities and should be further investigated. These activities justified the ethnomedical uses of these plants. PMID:20162089
Aladesanmi, A J; Iwalewa, E O; Adebajo, A C; Akinkunmi, E O; Taiwo, B J; Olorunmola, F O; Lamikanra, A
Genotoxic agents detected by plant bioassays.
Seven higher plant species (Allium cepa, Arabidopsis thaliana, Glycine max, Hordeum vulgaris. Tradescantia paludosa, Vicia faba, and Zea mays) were reviewed for their ability to detect genotoxicity of chemical agents under the U.S. Environmental Protection Agency (U.S. EPA) Gene-Tox program in the late 1970s. Six bioassays-Allium and Vicia root tip chromosome breaks, Tradescantia chromosome break, Tradescantia micronucleus, Tradescantia-stamen-hair mutation, and Arabidopsis-mutation bioassays- were established from four plant systems that are currently in use for detecting the genotoxicity of environmental agents. Under the Gene-Tox program, the Crepis capillaris-chromosome-aberration test was added to the existing six bioassays. The current review is limited to chemical agents that exhibit a positive response to any of these seven plant bioassays. From 158 articles reviewed, 84 chemicals were compiled in three categories: carcinogens, clastogens, and mutagens. As none of these plant bioassays can detect tumor initiation or cancerous growth, the chemicals were categorized as carcinogens based on their characteristics defined by the U.S. EPA's Superfund Priority 1 List and/or by the chemical listings of the Sigma and Aldrich Chemical Companies. Certain mutagens were categorized in the same manner in addition to the agents detected as mutagens by these plant bioassays. PMID:15835495
Ma, Te-Hsiu; Cabrera, Guillermo L; Owens, Elizabeth
Photo induced silver on nano titanium dioxide as an enhanced antimicrobial agent for wool.
In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO(2) as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO(2) nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO(2) on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM). PMID:21474327
Montazer, Majid; Behzadnia, Amir; Pakdel, Esfandiar; Rahimi, Mohammad Karim; Moghadam, Mohammad Bameni
Antimicrobial activity of selected South African medicinal plants
Background Nearly 3,000 plant species are used as medicines in South Africa, with approximately 350 species forming the most commonly traded and used medicinal plants. In the present study, twelve South African medicinal plants were selected and tested for their antimicrobial activities against eight microbial species belonging to fungi, Mycobacteria, Gram-positive and Gram-negative bacteria. Methods The radiometric respiratory technique using the BACTEC 460 system was used for susceptibility testing against Mycobacterium tuberculosis, and the liquid micro-broth dilution was used for other antimicrobial assays. Results The results of the minimal inhibitory concentration (MIC) determinations indicated that the methanol extracts from Acacia karoo, Erythrophleum lasianthum and Salvia africana were able to prevent the growth of all the tested microorganisms. All other samples showed selective activities. MIC values below 100??g/ml were recorded with A. karoo, C. dentate, E. lasianthum, P. obligun and S. africana on at least one of the nine tested microorganisms. The best activity (MIC value of 39.06??g/ml) was noted with S. africana against E. coli, S. aureus and M. audouinii, and Knowltonia vesitoria against M. tuberculosis. Conclusion The overall results of the present work provide baseline information for the possible use of the studied South African plant extracts in the treatment of microbial infections.
Immobilized lactoferrin (Im-LF) antimicrobial agents and uses thereof
US Patent & Trademark Office Database
Disclosed is a composition of matter comprising a defined dispersion of lactoferria immobilized on a naturally occuring substrate via the N-terminus region of the lactoferrin. Compositions comprising immobilized lactoferrin (Im-LF) are used in a method for reducing the microbial contamination of a composition subject to microbial contamination, which is also disclosed, and which encompasses a method for reducing the microbial contamination of a foodstuff, such as a meat product. Foodstuffs treated by the method are disclosed, including meat products. A method of inhibiting the growth and/or adhesion of a microbial species on a food-contacting surface f a material for food packaging or food handling with Im-LF is also disclosed. Food containers and food-handling implements so treated are also disclosed, as are antimicrobial cleansers, polishes, paints, sprays, soaps, or detergents containing Im-LF for applying to an inanimate surface.
Copper as an antimicrobial agent against opportunistic pathogenic and multidrug resistant Enterobacter bacteria.
Infections by Enterobacter species are common and are multidrug resistant. The use of bactericidal surface materials such as copper has lately gained attention as an effective antimicrobial agent due to its deadly effects on bacteria, yeast, and viruses. The aim of the current study was to assess the antibacterial activity of copper surfaces against Enterobacter species. The antibacterial activity of copper surfaces was tested by overlying 5×10(6) CFU/ml suspensions of representative Enterobacter strains and comparing bacterial survival counts on copper surfaces at room temperature. Iron, stainless steel, and polyvinylchloride (PVC) were used as controls. The mechanisms responsible for bacterial killing on copper surfaces were investigated by a mutagenicity assay of the D-cycloserin (cyclA gene), single cell gel electrophoresis, a staining technique, and inductively coupled plasma mass spectroscopy. Copper yielded a significant decrease in the viable bacterial counts at 2 h exposure and a highly significant decrease at 4 h. Loss of cell integrity and a significantly higher influx of copper into bacterial cells exposed to copper surfaces, as compared to those exposed to the controls, were documented. There was no increase in mutation rate and DNA damage indicating that copper contributes to bacterial killing by adversely affecting cellular structure without directly targeting the genomic DNA. These findings suggest that copper's antibacterial activity against Enterobacter species could be utilized in health care facilities and in food processing plants to reduce the bioburden, which would increase protection for susceptible members of the community. PMID:22923106
Tian, Wen-Xiao; Yu, Shi; Ibrahim, Muhammad; Almonaofy, Abdul Wareth; He, Liu; Hui, Qiu; Bo, Zhu; Li, Bin; Xie, Guan-Lin
In vitro synergy, pharmacodynamics, and postantibiotic effect of 11 antimicrobial agents against Rhodococcus equi.
There are no studies investigating interactions between clarithromycin or azithromycin and rifampin or other commonly used antimicrobial agents against virulent isolates of Rhodococcus equi. In addition, there is no published data on the postantibiotic effects (PAEs) and pharmacodynamics properties of antimicrobial agents against R. equi. The objectives were to assess in vitro interactions, pharmacodynamics, and PAEs of 11 antimicrobial agents belonging to various antimicrobial classes against R. equi. Antimicrobial agents investigated (erythromycin, clarithromycin, azithromycin, rifampin, amikacin, gentamicin, enrofloxacin, vancomycin, imipenem, ceftiofur, and doxycycline) were selected based on in vitro activity against large numbers of isolates of R. equi and frequency of use in foals or humans infected with R. equi. Three virulent strains of R. equi were evaluated by time-kill curves and checkerboard assays, and the postantibiotic effect was measured at 5×MIC. Only amikacin, gentamicin, enrofloxacin, and vancomycin were bactericidal against R. equi. Combinations including a macrolide (erythromycin, clarithromycin, azithromycin) and either rifampin or doxycycline, and the combination doxycycline-rifampin were synergistic. Combinations containing amikacin and erythromycin, clarithromycin, azithromycin, or rifampin and the combination gentamicin-rifampin were antagonistic. The PAEs of rifampin, erythromycin, clarithromycin, vancomycin, and doxycycline were relatively long with median values ranging between 4.5 and 6.5h. Azithromycin, gentamicin, and imipenem had intermediate PAEs ranging between 3.3 and 3.5h. Amikacin, enrofloxacin, and ceftiofur had shorter PAEs ranging between 1.3 and 2.1h. Gentamicin, amikacin, enrofloxacin, and doxycycline exhibited concentration-dependent activity whereas erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, imipenem, and vancomycin exhibited time-dependent activity against R. equi. PMID:22704561
Gigučre, Steeve; Lee, Elise A; Guldbech, Kristen M; Berghaus, Londa J
Analysis of Inorganic Antimicrobial Agents in Antimicrobial Products: Evaluation of a Screening Method by X-ray Fluorescence Spectrometry and the Measurement of Metals by Inductively Coupled Plasma Atomic Emission Spectroscopy
Antimicrobial agents used in antimicrobial products are classified into inorganic, organic, and natural organic compounds. Inorganic agents, such as Cu, Zn, and Ag compounds, are known to be relatively safe, and these agents are used in many kinds of products. Patients with metal allergy and infants should avoid coming in contact with products in which inorganic agents are used at
Harunobu Nakashima; Tomoko Ooshima
Screening of some medicinal plants of Ethiopia for their anti-microbial properties and chemical profiles.
In the indigenous health care delivery system of Ethiopia, numerous plant species are used to treat diseases of infectious origin. Regardless of the number of species, if any of such claims could be verified scientifically, the potential significance for the improvement of the health care services would be substantial. The objective of this study was, therefore, to determine the presence of anti-microbial activity in the crude extracts of some of the commonly used medicinal plants as well as to identify the class of compounds in the plants that were subjected to such screening. Thus, the crude methanol, petroleum ether and aqueous extracts of 67 plant species were subjected to preliminary screening against 10 strains of bacterial species and 6 fungal strains using the agar dilution method. A sample concentration of 250-2000 microg/ml and 500-4000 microg/ml were used for the bacterial and fungal pathogens, respectively. The results indicated that 44 different plant species exhibited activity against one or more of the bacteria while one species, viz., Albizzia gummifera showed activity against all the 10 bacteria at different gradient of dilution. Twenty three species inhibited or retarded growth of one or more organisms at dilution as low as 250 microg/ml. Extracts of same plants species were also tested against six different fungal pathogenic agents of which eight species showed growth inhibition against one or more of the organisms. Trichila emetica and Dovyalis abyssinica, which inhibited growth of four and five fungal strains at 100 microg/ml concentration, respectively, were the most promising plants. Chemical screening conducted on the extracts of all the plants showed the presence of several secondary metabolites, mainly, polyphenols, alkaloids, tannins sterols/terpenes, saponins and glycosides. The plants containing more of these metabolites demonstrated stronger anti-microbial properties stressing the need for further investigations using fractionated extracts and purified chemical components. PMID:15740876
Geyid, Aberra; Abebe, Dawit; Debella, Asfaw; Makonnen, Zewdneh; Aberra, Frehiwot; Teka, Frehiwot; Kebede, Tesfaye; Urga, Kelbessa; Yersaw, Kidist; Biza, Teklele; Mariam, Bisrat Haile; Guta, Mulugeta
The in vitro efficacy of antimicrobial agents against the pathogenic free-living amoeba Balamuthia mandrillaris.
The free-living amoeba Balamuthia mandrillaris causes usually fatal encephalitis in humans and animals. Only limited studies have investigated the efficacy of antimicrobial agents against the organism. Assay methods were developed to assess antimicrobial efficacy against both the trophozoite and cyst stage of B. mandrillaris (ATCC 50209). Amphotericin B, ciclopirox olamine, miltefosine, natamycin, paromomycin, pentamidine isethionate, protriptyline, spiramycin, sulconazole and telithromycin had limited activity with amoebacidal levels of > 135-500 ?M. However, diminazene aceturate (Berenil(®) ) was amoebacidal at 7.8 ?M and 31.3-61.5 ?M for trophozoites and cysts, respectively. Assays for antimicrobial testing may improve the prognosis for infection and aid in the development of primary selective culture isolation media. PMID:23869955
Ahmad, Arine F; Heaselgrave, Wayne; Andrew, Peter W; Kilvington, Simon
Preliminary screening of some traditional zulu medicinal plants for anti-inflammatory and anti-microbial activities
Aqueous and methanolic extracts from different parts of nine traditional Zulu medicinal plants, of the Vitaceae from KwaZulu-Natal, South Africa were evaluated for therapeutic potential as anti-inflammatory and anti-microbial agents. Of the twenty-nine crude extracts assayed for prostaglandin synthesis inhibitors, only five methanolic extracts of Cyphostemma natalitium-root, Rhoicissus digitata-leaf, R. rhomboidea-root, R. tomentosa-leaf\\/stem and R. tridentata-root showed significant inhibition of
J. Lin; A. R. Opoku; M. Geheeb-Keller; A. D. Hutchings; S. E. Terblanche; A. K. Jager; J. van Staden
Quaternized N-substituted carboxymethyl chitosan derivatives as antimicrobial agents.
Introduction of quaternary ammonium moieties into N-substituted carboxymethyl chitosan (N-substituted CMCh) derivatives enhances their biological activity. Several derivatives of CMCh having a variety of N-aryl substituents bearing either electron-donating or electron withdrawing groups have been synthesized by the reaction between amino group of CMCh with various aromatic aldehydes under acidic conditions, followed by reduction of the produced Schiff base derivatives with sodium cyanoborohydride. Each of the reduced derivatives was further quaternized using N-(3-chloro-2-hydroxy-propyl)trimethylammonium chloride (Quat-188). The resulting quaternized materials were characterized by FTIR and (1)H NMR spectroscopy. Their antibacterial activities against Streptococcus pneumoniae (S. pneumonia, RCMB 010010), Bacillis subtilis (B. subtilis, RCMB 010067), as Gram positive bacteria and against Escherichia coli (E. coli, RCMB 010052) as Gram negative bacteria and their antifungal activities against Aspergillus fumigatus (A. fumigates, RCMB 02568), Geotricum candidum (G. candidum, RCMB 05097), and Candida albicans (C. albicans, RCMB 05031) were examined using agar disk diffusion method. The results indicated that all the quaternized derivatives showed better antimicrobial activities than that of CMCh. These derivatives are highly potent against Gram positive bacteria compared to Gram negative bacteria. This is illustrated for example as the values of minimum inhibitory concentration (MIC) of Q4NO2-BzCMCh against B. subtilis and S. pneumonia were 6.25 and 12.5 ?g/mL, respectively corresponded to 20.0 ?g/mL against E. coli. The antimicrobial activity of quaternized N-aryl CMCh derivatives affected by not only the nature of the microorganisms but also by the nature, position and number of the substituent groups on the phenyl ring. Thus while the derivatives with groups of electron withdrawing nature show higher inhibition zone diameter and lower MIC values relative to that of those having electron-donating nature, the non-substituted derivative lies between these two extremes. Antibacterial activities of Q4NO2-BzCMCh, Q3Cl-BzCMCh and Q3Br-BzCMCh against E. coli are nearly equivalent to that of the standard drug Gentamycin. Q3Br-BzCMCh emerged almost equivalent antibacterial activity to Ampicillin against S. pneumonia. PMID:23732327
Mohamed, Nadia A; Sabaa, Magdy W; El-Ghandour, Ahmed H; Abdel-Aziz, Marwa M; Abdel-Gawad, Omayma F
In vitro testing of antimicrobial agents for proliferative enteropathy (ileitis)
Summary: Proliferative enteropathy (ileitis) is a common disease of grower and finisher pigs. Recent studies by the au- thors have illustrated reliable methods of in vitro culture of the etiologic agent, an obligate intracellular bacterium, known as ileal symbiont (IS) intracellularis.Characteristic le- sions of proliferative enteropathy are reproduced when IS intracellularis is used as oral inocula in challenge experi- ments
Steven McOrist; Connie J. Gebhart
Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.
The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods. PMID:16831479
Al-Bakri, Amal G; Afifi, Fatma U
Systematic study of non-natural short cationic lipopeptides as novel broad-spectrum antimicrobial agents.
We describe the design and synthesis of a new series of non-natural short cationic lipopeptides (MW = 700) as antimicrobial agents. All of the synthesized lipopeptides were tested against a range of microbes such as Gram-positive, Gram-negative bacteria, fungi including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). By systematic study of design template, we found that three ornithine residues conjugated with myristic acid are minimum requirement for a compound to be an antimicrobial agent. The most potent lipopeptide LP16 possesses broad-spectrum antimicrobial activity and has MICs in the range of 1.5-6.25 ?g/mL against Escherichia coli, S. aureus, Pseudomonas aeruginosa, Bacillus subtilis, and MRSE. All lipopeptides showed high selectivity toward microbial strains as compared to human red blood cells (HC50 > 250 ?g/mL). Moreover, most potent lipopeptides (LP16 and LP23) did not induce drug resistance in S. aureus even after 15 rounds of passaging. In addition, a representative lipopeptide (LP16) showed tryptic stability for 24 h. These results suggest the potential of short cationic lipopeptides to boost the discovery of future antimicrobial therapeutics. PMID:23819506
Lohan, Sandeep; Cameotra, Swaranjit S; Bisht, Gopal S
Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.
The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens. PMID:23444311
Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia
In Vitro Activities of SCH27899 Alone and in Combination with 17 Other Antimicrobial Agents
SCH27899, an everninomicin antibiotic, was tested for its in vitro activity against 718 bacterial isolates representing 27 species. The Enterobacteriaceae and nonenteric gram-negative bacilli were resistant to ?8.0 ?g/ml, but all others were inhibited by ?1.0 ?g/ml. When tested in combination with 17 other antimicrobial agents against 110 strains, SCH27899 demonstrated no significant antagonism or synergy. Consequently, combination therapy is not contraindicated.
Fuchs, Peter C.; Barry, Arthur L.; Brown, Steven D.
Inhibition of triazolam clearance by macrolide antimicrobial agents: In vitro correlates and dynamic consequences
Background: Macrolide antimicrobial agents may impair hepatic clearance of drugs metabolized by cytochrome P4503A isoforms. Potential interactions of triazolam, a substrate metabolized almost entirely by cytochrome P4503A in humans, with 3 commonly prescribed macrolides were identified using an in vitro metabolic model. The actual interactions, and their pharmacodynamic consequences, were verified in a controlled clinical study.Methods: In an in vitro
David J. Greenblatt; Lisa L. von Moltke; Jerold S. Harmatz; Molly Counihan; Jennifer A. Graf; Anna Liza B. Durol; Polyxane Mertzanis; Su Xiang Duan; C. Eugene Wright; Richard I. Shader
Chewing gum of antimicrobial decapeptide (KSL) as a sustained antiplaque agent: Preformulation study
The purpose of this study was to investigate the potential of KSL, an antimicrobial decapeptide, which has been shown to inhibit the growth of oral bacterial strains associated with caries development and plaque formation, to act as an antiplaque agent in a chewing gum formulation. A reversed-phase high-performance liquid chromatography method was developed for KSL and found to be stability-indicating.
Dong Hee Na; Jabar Faraj; Yilmaz Capan; Kai P. Leung; Patrick P. DeLuca
The therapeutic effect of 16 antimicrobial agents on Cryptosporidium infection in mice.
The therapeutic efficiency of 16 anti-microbial agents (Ethopabate, Nicarbazin, Sulphaquinoxaline, Furaltadone, Enterolyte-N, Sulphamethazine, Trinamide, Amprol, Phenamidine, Zoaquin, Halofuginone, Salinomycin, Monensin, Emtryl, Arprinocid and Amprolium) were examined against Cryptosporidium infections in mice. The Cryptosporidium was originally isolated from a field outbreak of calf diarrhoea. The drugs neither prevented nor modified the course of the infection as compared with infected, untreated mice. PMID:7115220
Tzipori, S R; Campbell, I; Angus, K W
The responsibility of the infectious disease community for the optimal use of antimicrobial agents.
Antimicrobial agents are a critical element of the therapeutic armamentarium of modern medicine. How well they are used reflects our ability to treat and prevent infectious diseases. The major consideration for proper usage is to select the optimal agent at the proper dosage. Secondary, but important concerns are to minimize the emergence of resistance and to provide health services at a reasonable cost. The infectious disease community must work in concert with the pharmaceutical industry to achieve these goals. The relations of infectious disease physicians with the industry have been remarkably effective in evaluating and introducing new drugs, however, it is natural that conflicts should arise. Although the overall accomplishments have been outstanding, there is considerable evidence that antimicrobial agents are often abused and used excessively. This paper outlines some of the issues of marketing and the problems inherent in industry-sponsored trials. As specialties other than infectious diseases have encountered major difficulties, it is timely that this society adopts a code of ethical conduct for its work with industrial sponsors and takes the initiative in developing programs for education of other physicians in the field of infectious diseases and antimicrobial therapy both in this country and in developing nations. PMID:3882848
Kunin, C M
The effect of various antimicrobial agents, such as aureomycin, terramycin, streptomycin, chloromycetin, penicillin, polymyxin, and sulfaguanidine on the development of massive dietary necrosis of the liver in rats has been studied. Delay in the production of hepatic necrosis was obtained from aureomycin and, to a lesser extent, from terramycin and streptomycin. Indication of temporary protection was shown by sulfaguanidine, whereas chloromycetin, polymyxin, and penicillin were not protective. B12, added alone, or in combination with aureomycin, to the basal experimental diet had no influence on the development of hepatic necrosis. A combination of pectin with streptomycin enhanced the protective effect of the antibiotic. All the antimicrobial agents tested, without relation to their effect on hepatic necrosis, produced temporary stimulation of growth in the experimental animals. The beneficial effect of aureomycin was not limited to the delay of hepatic necrosis but manifested itself also in the prevention of hepatic cirrhosis in rats fed a low protein (casein)-high fat diet. In contrast to control animals showing the usual combination of cirrhosis and renal changes, the rats receiving supplements of aureomycin were free of both cirrhosis and renal changes. The rats receiving aureomycin took more food in and gained weight. No microscopic alterations were seen in the pancreas of the control rats with cirrhosis. In both groups of experiments (necrosis and cirrhosis) the antimicrobial agents, with the exception of penicillin, were given mixed with the food. Their possible effect on the intestinal flora is discussed.
Gyorgy, Paul; Stokes, Joseph; Goldblatt, Harry; Popper, Hans
Expression of tmRNA in mycobacteria is increased by antimicrobial agents that target the ribosome.
The specialized RNA, tmRNA, is a central component of prokaryote trans-translation; a process that salvages stalled translational complexes. Evidence from other bacteria suggested that exposure to ribosome inhibitors elevated tmRNA levels, although it was unclear whether such changes resulted from increased tmRNA synthesis. Consequently, this study was initiated to determine the effect of ribosome inhibitors on the expression of tmRNA in mycobacteria. Exposure of Mycobacterium smegmatis to ribosome-targeting antimicrobial agents was associated with increased levels of the tmRNA precursor, pre-tmRNA, and mature tmRNA. For example, exposure to 16 ?g mL?ą erythromycin for 3 h increased pre-tmRNA and tmRNA by 18- and 6-fold, respectively. Equivalent results were found following exposure of Mycobacterium bovis BCG to streptomycin. Exposure to antimicrobial agents with nonribosome targets did not affect tmRNA levels. The increased tmRNA levels were associated with increased output from the ssrA promoter, which controls tmRNA transcription, without evidence of a change in tmRNA degradation. These results suggest that the upregulation of tmRNA expression was an important response of bacteria to exposure to ribosome-inhibiting antimicrobial agents. PMID:21718348
Andini, Nadya; Nash, Kevin A
Effects of antimicrobial agents on growth and chemotaxis of Trichomonas vaginalis.
The motility of viable Trichomonas vaginalis organisms is readily demonstrable in a clinical wet mount or cultured specimens. We attempted to determine whether migration is a dynamic process such that the organisms move to avoid exposure to toxic antimicrobial agents. With the use of axenic cultures of T. vaginalis that were radiolabeled and assayed for chemotaxis in plastic multiwelled plates with a membrane filter inserted to trap organisms, the response of clinical isolates to various antimicrobial agents was studied. Chemotaxis was readily demonstrable and dependent upon factors including time of incubation, media used, and viscosity of media. Nitroimidazoles (e.g., metronidazole) which readily inhibited the growth of these organisms also caused significant chemorepulsion after minutes of exposure. The antifungal imidazoles ketoconazole and miconazole inhibited growth nearly as readily and caused chemorepulsion, but to a lesser degree. The spermicide Nonoxynol-9 also inhibited growth and caused significant chemorepulsion. The minimal concentrations of many compounds which inhibited growth were very similar to those which caused significant chemorepulsion. Imidazole and antibiotics (e.g., penicillin) which did not inhibit growth did not induce any chemotactic effects. Chemotaxis of T. vaginalis is an active and dynamic process, and the organisms display chemorepulsion shortly after exposure to toxic antimicrobial agents, well before toxicity can be demonstrated. PMID:3264130
Sugarman, B; Mummaw, N
Effects of antimicrobial agents on growth and chemotaxis of Trichomonas vaginalis.
The motility of viable Trichomonas vaginalis organisms is readily demonstrable in a clinical wet mount or cultured specimens. We attempted to determine whether migration is a dynamic process such that the organisms move to avoid exposure to toxic antimicrobial agents. With the use of axenic cultures of T. vaginalis that were radiolabeled and assayed for chemotaxis in plastic multiwelled plates with a membrane filter inserted to trap organisms, the response of clinical isolates to various antimicrobial agents was studied. Chemotaxis was readily demonstrable and dependent upon factors including time of incubation, media used, and viscosity of media. Nitroimidazoles (e.g., metronidazole) which readily inhibited the growth of these organisms also caused significant chemorepulsion after minutes of exposure. The antifungal imidazoles ketoconazole and miconazole inhibited growth nearly as readily and caused chemorepulsion, but to a lesser degree. The spermicide Nonoxynol-9 also inhibited growth and caused significant chemorepulsion. The minimal concentrations of many compounds which inhibited growth were very similar to those which caused significant chemorepulsion. Imidazole and antibiotics (e.g., penicillin) which did not inhibit growth did not induce any chemotactic effects. Chemotaxis of T. vaginalis is an active and dynamic process, and the organisms display chemorepulsion shortly after exposure to toxic antimicrobial agents, well before toxicity can be demonstrated.
Sugarman, B; Mummaw, N
Peptidotriazoles with antimicrobial activity against bacterial and fungal plant pathogens.
We designed and prepared peptidotriazoles based on the antimicrobial peptide BP100 (LysLysLeuPheLysLysIleLeuLysTyrLeu-NH(2)) by introducing a triazole ring in the peptide backbone or onto the side chain of a selected residue. These compounds were screened for their in vitro growth inhibition of bacterial and fungal phytopathogens, and for their cytotoxic effects on eukaryotic cells and tobacco leaves. Their proteolytic susceptibility was also analyzed. The antibacterial activity and the hemolysis were influenced by the amino acid that was modified with the triazole as well as by the absence of presence of a substituent in this heterocyclic ring. We identified sequences active against the bacteria Xanthomonas axonopodis pv. vesicatoria, Erwinia amylovora, Pseudomonas syringae pv. syringae (MIC of 1.6-12.5 ?M), and against the fungi Fusarium oxysporum (MIC<6.2-12.5 ?M) with low hemolytic activity (0-23% at 50 ?M), high stability to protease digestion and no phytotoxicity. These peptidotriazoles constitute good candidates to design new antimicrobial agents. PMID:22198367
Güell, Imma; Micaló, Lluís; Cano, Laura; Badosa, Esther; Ferre, Rafael; Montesinos, Emilio; Bardají, Eduard; Feliu, Lidia; Planas, Marta
DNA minor groove binders as potential antitumor and antimicrobial agents.
DNA minor groove binders constitute an important class of derivatives in anticancer therapy. Some of these compounds form noncovalent complexes with DNA (e.g., distamycin A, Hoechst 33258, and pentamidine) while others DNA-binding compounds (such as CC-1065) cause cleavages in the DNA backbone. In this article, we have reviewed the minor groove binders currently in preclinical evaluation in the last years. Diarylamidines such as DAPI, berenil, and pentamidine; bis-benzimidazoles such as Hoechst 33258; ecteinascidins, pyrrololo [2,1-c]-[1,4]-benzodiazepines (PBDs), CC-1065, and distamycins are the classes discussed in this review article. A special section has been dedicated to hybrid molecules resulted by the combination of two minor groove binders, especially for derivatives of naturally occurring antitumor agents, such as anthramycin or the alkylating unit of the antibiotic CC-1065, and distamycin frames. PMID:15170593
Baraldi, Pier Giovanni; Bovero, Andrea; Fruttarolo, Francesca; Preti, Delia; Tabrizi, Mojgan Aghazadeh; Pavani, Maria Giovanna; Romagnoli, Romeo
Antimicrobial and toxicological activities of five medicinal plant species from Cameroon Traditional Medicine
Background Infectious diseases caused by multiresistant microbial strains are on the increase. Fighting these diseases with natural products may be more efficacious. The aim of this study was to investigate the in vitro antimicrobial activity of methanolic, ethylacetate (EtOAc) and hexanic fractions of five Cameroonian medicinal plants (Piptadeniastum africana, Cissus aralioides, Hileria latifolia, Phyllanthus muellerianus and Gladiolus gregasius) against 10 pathogenic microorganisms of the urogenital and gastrointestinal tracts. Methods The fractions were screened for their chemical composition and in vivo acute toxicity was carried out on the most active extracts in order to assess their inhibitory selectivity. The agar well-diffusion and the micro dilution methods were used for the determination of the inhibition diameters (ID) and Minimum inhibitory concentrations (MIC) respectively on 8 bacterial species including two Gram positive species (Staphylococcus aureus, Enterococcus faecalis), and six Gram negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Shigella flexneri, Salmonella typhi) and two fungal isolates (Candida albicans, Candida krusei). The chemical composition was done according to Harbone (1976), the acute toxicity evaluation according to WHO protocol and the hepatic as well as serum parameters measured to assess liver and kidney functions. Results The chemical components of each plant's extract varied according to the solvent used, and they were found to contain alkaloids, flavonoids, polyphenols, triterpens, sterols, tannins, coumarins, glycosides, cardiac glycosides and reducing sugars. The methanolic and ethylacetate extracts of Phyllanthus muellerianus and Piptadeniastum africana presented the highest antimicrobial activities against all tested microorganisms with ID varying from 8 to 26 mm and MIC from 2.5 to 0.31 mg/ml. The in vivo acute toxicity study carried out on the methanolic extracts of Phyllanthus muellerianus and Piptadeniastrum africana indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs. Conclusion These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents. Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine
Effect of ionizing energy on extracts of Quillaja saponaria to be used as an antimicrobial agent on irradiated edible coating for fresh strawberries
NASA Astrophysics Data System (ADS)
Incorporating antimicrobial compounds into edible films or coatings provides a novel way to improve the safety and shelf life of ready-to-eat foods. Diverse studies with Quillaja saponaria Mol. (popularly named quillay) extracts have demonstrated their potential as antifungal agents against phytopathogenic fungi. Crosslinking induced by ionizing radiation is an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on milk proteins. However there are few reports about the effects of ?-radiation on plant extracts. The aim of this work was to evaluate the effect of ionizing radiation (0, 5, 10, 15, 20, 25 and 35 kGy) on extracts prepared from in vitro plants of Q. saponaria to be used as antimicrobial agent in irradiated edible coating based on calcium caseinate and whey protein isolated, and also to establish the concentration of Q. saponaria extract to be added as an antifungal agent in the coating. Gamma irradiation since 15 kGy affects negatively the antimicrobial activity and metabolites composition of extract of Q. saponaria by reducing compounds of phenolic nature. Otherwise no effect on saponins profile was observed even at higher doses. It was possible to conclude that the antifungal activity of Q. saponaria extract is mainly related to phenolic compounds content. In addition, our work also shows that to obtain an efficient antifungal protection is necessary to add a minimum concentration of 6% of the extract after the coating irradiation.
Zúńiga, G. E.; Junqueira-Gonçalves, M. P.; Pizarro, M.; Contreras, R.; Tapia, A.; Silva, S.
Morphological and biochemical changes in Pseudomonas fluorescens biofilms induced by sub-inhibitory exposure to antimicrobial agents.
Confocal laser scanning microscopy (CLSM) and scanning transmission X-ray microscopy (STXM) were used to examine the morphological and biochemical changes in Pseudomonas fluorescens biofilms grown in the presence of subinhibitory concentrations of 4 antimicrobial agents: triclosan, benzalkonium chloride, chlorhexidine dihydrochloride, and trisodium phosphate. CLSM analyses using the stains SYTO9 and propidium iodide indicated that the antimicrobial agents affected cell membrane integrity and cellular density to differing degrees. However, fluorescein diacetate assays and plate counts demonstrated that the cells remained metabolically active. Fluorescent lectin binding assays showed that changes in the arrangement and composition of the exopolymer matrix of the biofilms also occurred and that these changes depended on the antimicrobial agent. Detailed single cell analyses using STXM provided evidence that the cell morphology, and the spatial distribution and relative amounts of protein, lipids and polysaccharides in the biofilms and within the cells were different for each antimicrobial. The distribution of chlorhexidine in the biofilm, determined from its distinct spectral signature, was localized mainly inside the bacterial cells. Each antimicrobial agent elicited a unique response; P. fluorescens cells and biofilms changed their morphology and architecture, as well as the distribution and abundance of biomacromolecules, in particular the exopolymer matrix. Pseudomonas fluorescens also exhibited adaptation to benzalkonium chloride at 10 microg/mL. Our observations point to the importance of changes in the quantity and chemistry of the exopolymeric matrix in the response to antimicrobial agents and suggest their importance as targets for control. PMID:19295649
Dynes, James J; Lawrence, John R; Korber, Darren R; Swerhone, George D W; Leppard, Gary G; Hitchcock, Adam P
Antimicrobial testing for surface-immobilized agents with a surface-separated live-dead staining method.
Modification of a traditional live-dead staining technique based on fluorescence microscopy has yielded an improved method capable of differentiating surface-immobilized antimicrobial agents from those agents acting via solution diffusion processes. By utilizing an inoculation chamber comprised of 50 µm polystyrene spheres as spacers between test substrate and coverslip control surfaces, three distinct bacterial cell populations can be probed by fluorescence microscopy for antimicrobial activity: (1) cells adhered to the coverslip, (2) cells adhered to the substrate, and (3) mobile cells in solution. Truly immobilized antimicrobial agents were found efficacious only at the substrate surface, while elutable agents were effective against all three populations. Glass surfaces derivatized with either quaternized poly dimethylaminoethylmethacrylate (pDMAEMA) or 3-(trimethoxysilyl) propyldimethyloctadecyl ammonium chloride (Si-QAC) were compared with bare glass control surfaces after contact and 4 h incubation with Staphylococcus aureus. pDMAEMA surfaces were both antimicrobial and immobilized, whereas the Si-QAC surfaces were only observed to be antimicrobial via active diffusion. In contrast to conventional thinking, Si-QAC surfaces showed no kill after removing all Si-QAC elutables via rinsing procedures. The semi-quantitative surface-separated live-dead staining (SSLDS) technique provides mechanistic insight and represents a significant improvement relative to current microbiological test methods for evaluating immobilized, antimicrobial agents. PMID:20824677
Green, John-Bruce D; Bickner, Susan; Carter, Phillip W; Fulghum, Timothy; Luebke, Michelle; Nordhaus, Mark A; Strathmann, Steve
Antimicrobial activity of essential oils and other plant extracts.
The antimicrobial activity of plant oils and extracts has been recognized for many years. However, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. In the present study, 52 plant oils and extracts were investigated for activity against Acinetobacter baumanii, Aeromonas veronii biogroup sobria, Candida albicans, Enterococcus faecalis, Escherichia col, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype typhimurium, Serratia marcescens and Staphylococcus aureus, using an agar dilution method. Lemongrass, oregano and bay inhibited all organisms at concentrations of < or = 2.0% (v/v). Six oils did not inhibit any organisms at the highest concentration, which was 2.0% (v/v) oil for apricot kernel, evening primrose, macadamia, pumpkin, sage and sweet almond. Variable activity was recorded for the remaining oils. Twenty of the plant oils and extracts were investigated, using a broth microdilution method, for activity against C. albicans, Staph. aureus and E. coli. The lowest minimum inhibitory concentrations were 0.03% (v/v) thyme oil against C. albicans and E. coli and 0.008% (v/v) vetiver oil against Staph. aureus. These results support the notion that plant essential oils and extracts may have a role as pharmaceuticals and preservatives. PMID:10438227
Hammer, K A; Carson, C F; Riley, T V
Mechanisms of Antiviral Action of Plant Antimicrobials against Murine Norovirus.
Numerous plant compounds have antibacterial or antiviral properties; however, limited research has been conducted with nonenveloped viruses. The efficacies of allspice oil, lemongrass oil, and citral were evaluated against the nonenveloped murine norovirus (MNV), a human norovirus surrogate. The antiviral mechanisms of action were also examined using an RNase I protection assay, a host cell binding assay, and transmission electron microscopy. All three antimicrobials produced significant reductions (P ? 0.05) in viral infectivity within 6 h of exposure (0.90 log10 to 1.88 log10). After 24 h, the reductions were 2.74, 3.00, and 3.41 log10 for lemongrass oil, citral, and allspice oil, respectively. The antiviral effect of allspice oil was both time and concentration dependent; the effects of lemongrass oil and citral were time dependent. Based on the RNase I assay, allspice oil appeared to act directly upon the viral capsid and RNA. The capsids enlarged from ?35 nm to up to 75 nm following treatment. MNV adsorption to host cells was not significantly affected. Alternatively, the capsid remained intact following exposure to lemongrass oil and citral, which appeared to coat the capsid, causing nonspecific and nonproductive binding to host cells that did not lead to successful infection. Such contrasting effects between allspice oil and both lemongrass oil and citral suggest that though different plant compounds may yield similar reductions in virus infectivity, the mechanisms of inactivation may be highly varied and specific to the antimicrobial. This study demonstrates the antiviral properties of allspice oil, lemongrass oil, and citral against MNV and thus indicates their potential as natural food and surface sanitizers to control noroviruses. PMID:24907316
Gilling, Damian H; Kitajima, Masaaki; Torrey, Jason R; Bright, Kelly R
Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?
The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly relevant in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means. PMID:19838557
Teles, Ricardo Palmier; Teles, Flavia Rocha Fonseca
In vitro susceptibility of upper respiratory tract pathogens to 13 oral antimicrobial agents.
An in vitro comparison of the activities of 13 oral antimicrobial agents against clinical isolates of bacteria commonly responsible for causing upper respiratory tract infections was performed. With regard to Haemophilus influenzae, beta-lactamase-negative strains were susceptible to amoxycillin, augmentin, cefaclor, erythromycin, trimethoprim, cotrimoxazole and tetracycline, with CL 284,635 being the most active agent. With the exception of amoxycillin these drugs were also active against beta-lactamase-producing strains. CL 284,635 was also very active against Branhamella catarrhalis isolates, including beta-lactamase-producing strains, but was less active against the Gram-positive bacteria tested. Cefadroxil, cephradine and cephalexin were mainly active against Gram-positive pathogens. Based on minimum inhibitory concentration determinations, cefaclor, augmentin and co-trimoxazole would be appropriate drugs for the treatment of those cases of otitis media and sinusitis where H. influenzae and Streptococcus pneumoniae are important pathogens provided they are susceptible to these agents. PMID:3660122
Liebowitz, L D; Saunders, J; Koornhof, H J
Effects of Slime Produced by Clinical Isolates of Coagulase-Negative Staphylococci on Activities of Various Antimicrobial Agents
A novel in vitro semiquantitative method was developed to investigate the influence of staphylococcal slime on the activities of 22 antimicrobial agents. Pefloxacin, teicoplanin, and vancomycin demonstrated remarkable decreases in efficacy: 30, 52, and 63%, respectively. The activity of rifampin was not significantly reduced (0.99%), whereas all other agents tested were modestly affected (<15% decrease). These data could be influential
Antimicrobial resistance of Listeria monocytogenes isolated from a poultry further processing plant.
The aim of this study was to compare antimicrobial resistance profiles of distinct types of Listeria monocytogenes isolated from a commercial poultry cooking plant. One hundred fifty-seven L. monocytogenes isolates representing 14 different actA types were tested for susceptibility to 19 antimicrobial drugs using the broth microdilution method. All isolates were susceptible to antimicrobials except for ceftriaxone (153 isolates [97%] intermediate or resistant), oxacillin with 2% NaCl (142 isolates [90%] resistant), ciprofloxacin (59 isolates [37%] intermediate or resistant), tetracycline (5 isolates [3%] resistant), clindamycin (43 isolates [27%] intermediate), linezolid (3 isolates [2%] intermediate), and trimethoprim/sulfamethoxazole (1 isolate [<1%] intermediate). Prevalence of antimicrobial resistance was low among all actA types. There was a low amount of diversity of resistotypes, which were defined in this study as subdivisions of actA types according to antimicrobial resistance profiles of the isolates. The five tetracycline-resistant isolates represented all the members of one actA type in lineage II. This study showed that antimicrobial resistance is not highly prevalent in L. monocytogenes from a poultry further processing environment. Types of L. monocytogenes as distinguished by actA sequencing do not predict antimicrobial resistance except possibly for tetracycline resistance. L. monocytogenes types that persist in a poultry cook plant are not related to antimicrobial resistance, and excluding tetracycline resistance, antimicrobial resistance does not seem to differ according to actA type or lineage. PMID:18564907
Lyon, Steven A; Berrang, Mark E; Fedorka-Cray, Paula J; Fletcher, Daniel L; Meinersmann, Richard J
The resistance to antimicrobial agents of Staphylococcus aureus isolated from the bovine udder.
Isolates of Staphylococcus aureus (total 1657) from bovine mastitis were collected from 13 laboratories throughout Australia from 1974 to 1979. They were tested for resistance to antimicrobial agents using an agar dilution method. Resistance shown was mainly to penicillin and streptomycin. Occasional strains were resistant to neomycin, lincomycin, erythromycin, tetracycline, chloramphenicol and furazolidone but multiple resistance was rare. No strain showed resistance to methicillin. Resistance to penicillin declined from 35% in 1974-75 to 7.1% in 1979. Most strains (1395) were retested to allow induction of penicillinase; 62% produced the enzyme. PMID:6914886
Frost, A J; O'Boyle, D
Piperidine-mediated synthesis of thiazolyl chalcones and their derivatives as potent antimicrobial agents.
A series of new thiazolyl chalcones, 1-[2-amino-4-methyl-1,3-thiazol-5-yl]-3-aryl-prop-2-en-1-one were prepared by piperidine mediated Claisen-Schmidt condensation of thiazolyl ketone with aromatic aldehyde. These chalcones on cyclisation gave 2-amino-6-(2-amino-4-methyl-1,3-thiazol-5-yl)-4-aryl-4H-pyridine-3-carbonitrile and 2-amino-6-(2-amino-4-methyl-1,3-thiazol-5-yl)-4-aryl-4H-pyran-3-carbonitrile. The result showed that the compounds exhibited marked potency as antimicrobial agents. PMID:21834630
Venkatesan, P; Maruthavanan, T
In-vitro susceptibility of clinical isolates of Serratia species to antimicrobial agents.
The in-vitro activities of 12 antimicrobial agents against a total of 80 clinical isolates of Serratia marcescens and Serratia liquefaciens were determined by a broth microdilution method. Ampicillin and cefazolin were totally inactive against these organisms. The other beta-lactam antibiotics such as piperacillin, cefotaxime, ceftazidime, and the aminoglycosides such as gentamicin, tobramycin and netilmicin showed poor or moderate activity against Serratia isolates. Aztreonam and amikacin inhibited most of the strains tested. Imipenem and ciprofloxacin were very active in inhibiting all strains. Within the genus, S. liquefaciens was more resistant to aztreonam, ceftazidime and amikacin than S. marcescens. PMID:2362189
Sofianou, D; Proya, E; Kondodimou, A
In Vitro Activity of Retapamulin against Staphylococcus aureus Resistant to Various Antimicrobial Agents
Retapamulin and six other antimicrobial agents were evaluated against 155 methicillin-resistant Staphylococcus aureus (MRSA) isolates, including strains resistant to vancomycin, linezolid, daptomycin, and mupirocin by microdilution tests. Time-kill assays were performed against representative MRSA, vancomycin-intermediate S. aureus (VISA), and vancomycin-resistant S. aureus (VRSA) isolates. Retapamulin and mupirocin demonstrated MIC90s of 0.12 ?g/ml and 8 ?g/ml, respectively, with resistance seen in 2.6% and 10% of isolates, respectively. Retapamulin maintained good activity against 94% (15/16) of mupirocin-resistant isolates.
Pawlak, Joan; Saravolatz, Stephanie N.; Johnson, Leonard B.
In Vitro Susceptibility of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis to Fifty-One Antimicrobial Agents
By a tube dilution assay technique, 51 antimicrobial agents were singly tested against 9 strains of Mycoplasma hyopneumoniae and 1 strain of M. hyorhinis for the purpose of obtaining information useful for selecting an agent for testing in vivo against porcine mycoplasmal pneumonia. Based on determining minimal inhibitory concentrations and chemically grouping the agents into nine classes, all M. hyopneumoniae strains were found resistant to penicillins and peptides and susceptible to sulfonamides and tetracyclines, and, in other classes, were either susceptible or resistant depending on the particular agent being tested. Strains were susceptible to the same 33 of the 51 agents. Minimal inhibitory concentrations ranged from 0.06 to 9.20 ?g/ml. M. hyorhinis was susceptible to 19 of the 33 agents that M. hyopneumoniae was susceptible to. Minimal inhibitory concentrations ranged from 0.03 to 8.10 ?g/ml. All strains of M. hyopneumoniae differed from M. hyorhinis in that they were susceptible to cephaloglycin and nitrofurazone.
Williams, Phletus P.
In the microbial transformation of 2-chloro-4-nitrophenol and its 2-aminotridecane compound salt, 2-chloro-4-nitrophenol was\\u000a found to be degraded to four metabolites only on using strains resistant to 2-chloro-4-nitrophenol. Sensitive strains lacked\\u000a this property. In the case of the 2-amino-tridecane compound salt, the first reaction produced by strains resistant to 2-chloro-4-nitrophenol\\u000a was dissociation of the compound salt into the two initial components,
A. ?apek; A. Šimek; J. Leiner; J. Weichet
Prevalence of Salmonella associated with chick mortality at hatching and their susceptibility to antimicrobial agents.
The prevalence of Salmonella associated mortality at hatching was investigated in three hatcheries in Jos, central Nigeria. Their susceptibility to antimicrobial agents was also evaluated. S. Kentucky and S. Hadar were isolated. While half of the isolates were from internal organs, 26.7% came from meconial swabs of dead-in-shell embryos, 17.8% from intestinal samples and 4.4% from egg shells. S. Hadar is known to colonise only the gut and is classified as non-invasive, but in this study 82% were obtained from internal organs which suggests that infections with this serotype may also cause invasive disease. Antimicrobial susceptibility tests showed a high prevalence of antimicrobial resistance in the study area with complete resistance to gentamycin, enrofloxacin, nalidixic acid, tetracycline and streptomycin and substantial resistance to triple sulphur and ciprofloxacin. Six multiple resistance profiles were recorded with a high level of multiple resistance to quinolones. Quinolone resistance has implications for veterinary and human therapy as their misuse in poultry could lead to the emergence of resistant animal and zoonotic pathogens. PMID:19643554
Muhammad, Maryam; Muhammad, Lawal U; Ambali, Abdul-Ganiyu; Mani, Aliyu U; Azard, Samuel; Barco, Lisa
Antimicrobial and cytotoxic activities screening of some Brazilian medicinal plants used in Governador Valadares district
Ethanol extracts from medicinal plants commonly used by Governador Valadares people were tested for antimicrobial activity and cytotoxicity (BST assay). The field survey was conducted during the years 1997-2000 by means of direct interviews with healing men (\\
Beatriz Gonçalves Brasileiro; Virgínia Ramos Pizziolo; Délio Soares Raslan; Claudia Mashrouah Jamal; Dâmaris Silveira
Bacterial inactivation using silver-coated magnetic nanoparticles as functional antimicrobial agents
The ability for silver nanoparticles to function as an antibacterial agent while being separable from the target fluids is important for bacterial inactivation in biological fluids. This report describes the analysis of the antimicrobial activities of silver-coated magnetic nanoparticles synthesized by wet chemical methods. The bacterial inactivation of several types of bacteria was analyzed, including Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (Pseudomonas aeruginosa, Enterobacter cloacae, and Escherichia coli). The results have demonstrated the viability of the silver-coated magnetic nanoparticles for achieving effective bacterial inactivation efficiency comparable to and better than silver nanoparticles conventionally used. The bacteria inactivation efficiency of our MZF@Ag nanoparticles were also determined for blood platelets samples, demonstrating the potential of utilization in inactivating bacterial growth in platelets prior to transfusion to ensure blood product safety, which also has important implications for enabling the capability of effective separation, delivery and targeting of the antibacterial agents.
Wang, Lingyan; Luo, Jin; Shan, Shiyao; Crew, Elizabeth; Yin, Jun; Zhong, Chuan-Jian; Wallek, Brandi; Wong, Season
Antimicrobial and antioxidant activities of plants from northeast of Mexico.
Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000??g?ml(-1). We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125??g?ml(-1)), C. glabrata (MICs 31.25??g?ml(-1)) and C. parapsilosis (MICs between 31.25 and 125??g?ml(-1)); Chrysanctinia mexicana against C. glabrata (MICs 31.25 ?g ml(-1)); Colubrina greggii against E. faecalis (MICs 250??g?ml(-1)) and Cordia boissieri against C. glabrata (MIC 125 ?g ml(-1)). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri. PMID:19770266
Salazar-Aranda, Ricardo; Pérez-López, Luis Alejandro; López-Arroyo, Joel; Alanís-Garza, Blanca Alicia; Waksman de Torres, Noemí
?-Lactone natural products and derivatives inactivate homoserine transacetylase, a target for antimicrobial agents.
Homoserine transacetylase (HTA) catalyzes the transfer of an acetyl group from acetyl-CoA to the hydroxyl group of homoserine. This is the first committed step in the biosynthesis of methionine (Met) from aspartic acid in many fungi, Gram-positive and some Gram-negative bacteria. The enzyme is absent in higher eukaryotes and is important for microorganism growth in Met-poor environments, such as blood serum, making HTA an attractive target for new antimicrobial agents. HTA catalyzes acetyl transfer via a double displacement mechanism facilitated by a classic Ser-His-Asp catalytic triad located at the bottom of a narrow actives site tunnel. We explored the inhibitory activity of several ?-lactones to block the activity of HTA. In particular, the natural product ebelactone A, a ?-lactone with a hydrophobic tail was found to be a potent inactivator of HTA from Haemophilus influenzae. Synthetic analogs of ebelactone A demonstrated improved inactivation characteristics. Covalent modification of HTA was confirmed by mass spectrometry, and peptide mapping identified Ser143 as the modified residue, consistent with the known structure and mechanism of the enzyme. These results demonstrate that ?-lactone inhibitors are excellent biochemical probes of HTA and potential leads for new antimicrobial agents. PMID:21522158
De Pascale, Gianfranco; Nazi, Ishac; Harrison, Paul H M; Wright, Gerard D
Morbidity and Mortality Weekly Report, Volume 54, Number RR-14, December 9, 2005. Recommended Antimicrobial Agents for Treatment and Postexposure Prophylaxis of Perturssis, 2005 CDC Guidelines.
National Technical Information Service (NTIS)
The recommendations in this report were developed to broaden the spectrum of antimicrobial agents that are available for treatment and postexposure prophylaxis of pertussis. They include updated information on macrolide agents other than erythromycin (azi...
T. Tiwari T. Murphy J. Moran
French Multicenter Study Involving Eight Test Sites for Radiometric Determination of Activities of 10 Antimicrobial Agents againstMycobacterium aviumComplex
The radiometric BACTEC 460-TB methodology hasfilled an increased need in the screening of a wide range of antimicrobial agents against Mycobacterium avium (MAC) isolates on a patient-to-patient basis. In this context, a multicenter study involving eight test sites across France was performed to determine the MICs of 10 antimicrobial agents for MAC organisms. The aim of the investigation was to
Search for antibacterial and antifungal agents from selected Indian medicinal plants.
A series of 61 Indian medicinal plants belonging to 33 different families used in various infectious disorders, were screened for their antimicrobial properties. Screening was carried out at 1000 and 500 microg/ml concentrations by agar dilution method against Bacillus cereus var mycoides, Bacillus pumilus, Bacillus subtilis, Bordetella bronchiseptica, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus faecalis, Candida albicans, Aspergillus niger and Saccharomyces cerevisiae. Twenty-eight plant extracts showed activity against at least one of the test organisms used in the screening. On the basis of the results obtained, we conclude that the crude extracts of Dorema ammoniacum, Sphaeranthus indicus, Dracaena cinnabari, Mallotus philippinensis, Jatropha gossypifolia, Aristolochia indica, Lantana camara, Nardostachys jatamansi, Randia dumetorum and Cassia fistula exhibited significant antimicrobial activity and properties that support folkloric use in the treatment of some diseases as broad-spectrum antimicrobial agents. This probably explains the use of these plants by the indigenous people against a number of infections. PMID:16678369
Kumar, V Prashanth; Chauhan, Neelam S; Padh, Harish; Rajani, M
Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants.
We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus and 16 Escherichia coli strains from human specimens was carried out using the dilution method in Mueller-Hinton agar. Some phenolic compounds with antimicrobial properties were established, and all EOs had a higher antimicrobial activity than the extracts. Matricaria chamomilla extract and E. uniflora EO were efficient against S. aureus strains, while E. uniflora and V. polyanthes extracts and V. polyanthes EO showed the best antimicrobial activity against E. coli strains. Staphylococcus aureus strains were more susceptible to the tested plant products than E. coli, but all natural products promoted antimicrobial growth inhibition. PMID:22007687
Silva, N C C; Barbosa, L; Seito, L N; Fernandes, A
Effects of Subtherapeutic Administration of Antimicrobial Agents to Beef Cattle on the Prevalence of Antimicrobial Resistance in Campylobacter jejuni and Campylobacter hyointestinalis†
The influence of antimicrobial agents on the development of antimicrobial resistance (AMR) in Campylobacter isolates recovered from 300 beef cattle maintained in an experimental feedlot was monitored over a 315-day period (11 sample times). Groups of calves were assigned to one of the following antimicrobial treatments: chlortetracycline and sulfamethazine (CS), chlortetracycline alone (Ct), virginiamycin, monensin, tylosin phosphate, and no antimicrobial agent (i.e., control treatment). In total, 3,283 fecal samples were processed for campylobacters over the course of the experiment. Of the 2,052 bacterial isolates recovered, 92% were Campylobacter (1,518 were Campylobacter hyointestinalis and 380 were C. jejuni). None of the antimicrobial treatments decreased the isolation frequency of C. jejuni relative to the control treatment. In contrast, C. hyointestinalis was isolated less frequently from animals treated with CS and to a lesser extent from animals treated with Ct. The majority (?94%) of C. jejuni isolates were sensitive to ampicillin, erythromycin, and ciprofloxacin, but more isolates with resistance to tetracycline were recovered from animals fed Ct. All of the 1,500 isolates of C. hyointestinalis examined were sensitive to ciprofloxacin. In contrast, 11%, 10%, and 1% of these isolates were resistant to tetracycline, erythromycin, and ampicillin, respectively. The number of animals from which C. hyointestinalis isolates with resistance to erythromycin and tetracycline were recovered differed among the antimicrobial treatments. Only Ct administration increased the carriage rates of erythromycin-resistant isolates of C. hyointestinalis, and the inclusion of CS in the diet increased the number of animals from which tetracycline-resistant isolates were recovered. The majority of C. hyointestinalis isolates with resistance to tetracycline were obtained from cohorts within a single pen, and most of these isolates were recovered from cattle during feeding of a forage-based diet as opposed to a grain-based diet. The findings of this study show that the subtherapeutic administration of tetracycline, alone and in combination with sulfamethazine, to feedlot cattle can select for the carriage of resistant strains of Campylobacter species. Considering the widespread use of in-feed antimicrobial agents and the high frequency of beef cattle that shed campylobacters, the development of AMR should be monitored as part of an on-going surveillance program.
Inglis, G. D.; McAllister, T. A.; Busz, H. W.; Yanke, L. J.; Morck, D. W.; Olson, M. E.; Read, R. R.
Search for antisickling agents from plants.
The sickle cell disease is fatal in nature. Thousands of children are dying off due to this health problem throughout the globe. Due to the rapid development of diagnosis and clinical managements such patients are living up to a respectable age. But as there is no permanent cure the patients are suffering from bone and joint pain, jaundice, hepato-splenomegaly, chronic infections etc. The main physiological complicacy is due to the polymerization of sickle hemoglobin (HbS), (sickling process) inside the red blood cell (RBC) of these patients during deoxygenating state. The change of RBC from spherical to sickle shape is due to the polymerization of mutant hemoglobin (HbS) inside the RBC and membrane distortion during anoxic condition. The mechanism and the process of sickling are very complex and multifactor in nature. To get rid from such complicacies it is necessary to suitably and accurately stop the sickling of RBC of the patients. The potential anti-sickling agents either from natural sources and/or synthetic molecules may be helpful for reducing the clinical morbidity of the patients. A lot of natural compounds from plant extracts have been tried by several workers in recent past. Most of the studies are based on in vitro red cell sickling studies and their mode of action has not been properly understood. Although, few studies have been in vivo in nature pertaining to transgenic sickle animal model, there is paucity of data on the human studies. The result of such studies although has shown some degree of success, a promising anti-sickling agent is yet to be established. PMID:23922457
Dash, Bisnu Prasad; Archana, Y; Satapathy, Nibarana; Naik, Soumendra Kumar
Search for antisickling agents from plants
The sickle cell disease is fatal in nature. Thousands of children are dying off due to this health problem throughout the globe. Due to the rapid development of diagnosis and clinical managements such patients are living up to a respectable age. But as there is no permanent cure the patients are suffering from bone and joint pain, jaundice, hepato-splenomegaly, chronic infections etc. The main physiological complicacy is due to the polymerization of sickle hemoglobin (HbS), (sickling process) inside the red blood cell (RBC) of these patients during deoxygenating state. The change of RBC from spherical to sickle shape is due to the polymerization of mutant hemoglobin (HbS) inside the RBC and membrane distortion during anoxic condition. The mechanism and the process of sickling are very complex and multifactor in nature. To get rid from such complicacies it is necessary to suitably and accurately stop the sickling of RBC of the patients. The potential anti-sickling agents either from natural sources and/or synthetic molecules may be helpful for reducing the clinical morbidity of the patients. A lot of natural compounds from plant extracts have been tried by several workers in recent past. Most of the studies are based on in vitro red cell sickling studies and their mode of action has not been properly understood. Although, few studies have been in vivo in nature pertaining to transgenic sickle animal model, there is paucity of data on the human studies. The result of such studies although has shown some degree of success, a promising anti-sickling agent is yet to be established.
Dash, Bisnu Prasad; Archana, Y.; Satapathy, Nibarana; Naik, Soumendra Kumar
Plant Derived Therapeutic Agents: The Indian Experience.
National Technical Information Service (NTIS)
Contents: Research and development for the utilisation of medicinal plants for therapeutic use; Traditional system remedies; Broad spectrum biological screening of plants; Cultivation of medicinal plants; Phytochemical industry; Regional medicinal plants ...
N. Anand
[Identification and susceptibility to antimicrobial agents of strictly anaerobic bacteria isolated from hospitalized patients].
The aim of this study was to identify anaerobic strains isolated in 2001 from clinical specimens obtained from patients of Warsaw hospital and to evaluate a susceptibility of these strains to antimicrobial agents. In 2001 two hundred and twenty five clinical strains of obligate anaerobes were cultured, which were identified in the automatic ATB system (bioMérieux, France) using biochemical tests API 20 A. Drug-susceptibility of strains was determined also in ATB system with the use of ATB ANA strips. C. difficile strains were isolated on selective CCCA medium. Toxins A/B of C. difficile directly in stool specimens were detected by means of ELISA test (TechLab, USA). Fifty four strains of Gram-negative anaerobes (B. fragilis strains dominated) and 171 strains of Gram-positive anaerobes (the greatest number of strains belonged to genus Peptostreptococcus) were cultured from clinical specimens. In the cases of antibiotic-associated diarrhea 28 C. difficile strains were isolated and C. difficile toxins A/B were detected in 39 stool samples. The most active in vitro antimicrobials against Gram-negative anaerobes were metronidazole, imipenem, ticarcillin combined with clavulanic acid and piperacillin with tazobactam. Gram-positive, clinical strains of anaerobes were the most susceptible in vitro to beta-lactam antibiotics combined with beta-lactamase inhibitors (amoxicillin/clavulanate, piperacillin/tazobactam, ticarcillin/clavulanate) and imipenem. PMID:12632658
Kot, Katarzyna; Rokosz, Alicja; Sawicka-Grzelak, Anna; ?uczak, Miros?aw
Phyllanthus wightianus Müll. Arg.: a potential source for natural antimicrobial agents.
Phyllanthus wightianus belongs to Euphorbiaceae family having ethnobotanical importance. The present study deals with validating the antimicrobial potential of solvent leaf extracts of P. wightianus. 11 human bacterial pathogens (Bacillus subtilis, Streptococcus pneumoniae, Staphylococcus epidermidis, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, Escherichia coli, Shigella flexneri, Proteus vulgaris, and Serratia marcescens) and 4 fungal pathogens (Candida albicans, Cryptococcus neoformans, Mucor racemosus, and Aspergillus niger) were also challenged with solvent leaf extracts usingagar well and disc diffusion methods. Further, identification of the active component present in the bioactive extract was done using GC-MS analysis. Results show that all extracts exhibited broad spectrum (6-29 mm) of antibacterial activity on most of the tested organisms. The results highlight the fact that the well in agar method was more effective than disc diffusion method. Significant antimicrobial activity was detected in methanol extract against S. pneumoniae (29 mm) with MIC and MBC values of 15.62 ?g/mL. GC-MS analysis revealed that 29 bioactive constituents were present in methanolic extract of P. wightianus, of which 9,12-octadecaenioic acid (peak area 22.82%; RT-23.97) and N-hexadecanoic acid (peak area 21.55% RT-21.796) are the major compounds. The findings of this study show that P. wightianus extracts may be used as an anti-infective agent in folklore medicine. PMID:24883301
Natarajan, D; Srinivasan, R; Shivakumar, M S
Phyllanthus wightianus M?ll. Arg.: A Potential Source for Natural Antimicrobial Agents
Phyllanthus wightianus belongs to Euphorbiaceae family having ethnobotanical importance. The present study deals with validating the antimicrobial potential of solvent leaf extracts of P. wightianus. 11 human bacterial pathogens (Bacillus subtilis, Streptococcus pneumoniae, Staphylococcus epidermidis, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, Escherichia coli, Shigella flexneri, Proteus vulgaris, and Serratia marcescens) and 4 fungal pathogens (Candida albicans, Cryptococcus neoformans, Mucor racemosus, and Aspergillus niger) were also challenged with solvent leaf extracts usingagar well and disc diffusion methods. Further, identification of the active component present in the bioactive extract was done using GC-MS analysis. Results show that all extracts exhibited broad spectrum (6–29?mm) of antibacterial activity on most of the tested organisms. The results highlight the fact that the well in agar method was more effective than disc diffusion method. Significant antimicrobial activity was detected in methanol extract against S. pneumoniae (29?mm) with MIC and MBC values of 15.62??g/mL. GC-MS analysis revealed that 29 bioactive constituents were present in methanolic extract of P. wightianus, of which 9,12-octadecaenioic acid (peak area 22.82%; RT-23.97) and N-hexadecanoic acid (peak area 21.55% RT-21.796) are the major compounds. The findings of this study show that P. wightianus extracts may be used as an anti-infective agent in folklore medicine.
Natarajan, D.; Srinivasan, R.; Shivakumar, M. S.
Antimicrobial effect of various combinations of plant extracts
The combined extracts of corni fructus, cinnamon and Chinese chive were used to evaluate its antimicrobial activity on common foodborne micro-organisms, including bacteria, yeasts and moulds. The combined extract (8:1:1, v\\/v\\/v) showed an entire antimicrobial spectrum and outstanding inhibitory effect. The combined extract was very stable under heat treatment. The inhibitory effect of the combined extract was greater with more
Pao-Chuan Hsieh; Jeng-Leun Mau; Shu-Hui Huang
Antibiofilm effect of plant derived antimicrobials on Listeria monocytogenes.
The present study investigated the efficacy of sub-inhibitory concentrations (SICs, concentrations not inhibiting bacterial growth) and bactericidal concentrations (MBCs) of four, generally recognized as safe (GRAS), plant-derived antimicrobials (PDAs) in inhibiting Listeria monocytogenes (LM) biofilm formation and inactivating mature LM biofilms, at 37, 25 and 4 °C on polystyrene plates and stainless-steel coupons. In addition, the effect of SICs of PDAs on the expression of LM genes critical for biofilm synthesis was determined by real-time quantitative PCR. The PDAs and their SICs used for inhibition of biofilm were trans-cinnamaldehyde (TC 0.50, 0.75 mM), carvacrol (CR 0.50, 0.65 mM), thymol (TY 0.33, 0.50 mM), and eugenol (EG 1.8, 2.5 mM), whereas the PDA concentrations used for inactivating mature biofilms were 5.0 and 10.0 mM (TC, CR), 3.3 and 5.0 mM (TY), 18.5 and 25.0 mM (EG). All PDAs inhibited biofilm synthesis and inactivated fully formed LM biofilms on both matrices at three temperatures tested (P < 0.05). Real-time quantitative PCR data revealed that all PDAs down-regulated critical LM biofilm-associated genes (P < 0.05). Results suggest that TC, CR, TY, and EG could potentially be used to control LM biofilms in food processing environments, although further studies under commercial settings are necessary. PMID:23764223
Upadhyay, Abhinav; Upadhyaya, Indu; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar
The ability of an antimicrobial agent to penetrate a biofilm is not correlated with its killing or removal efficiency.
The penetration ability of 12 antimicrobial agents, including antibiotics and biocides, was determined against biofilms of B. cereus and P. fluorescens using a colony biofilm assay. The surfactants benzalkonium chloride (BAC) and cetyltrimethyl ammonium bromide (CTAB), and the antibiotics ciprofloxacin and streptomycin were of interest due to their distinct activities. Erythromycin and CTAB were retarded by the presence of biofilms, whereas ciprofloxacin and BAC were not. The removal and killing efficacies of these four agents was additionally evaluated against biofilms formed in microtiter plates. The most efficient biocide was CTAB for both bacterial biofilms. Ciprofloxacin was the best antibiotic although none of the selected antimicrobial agents led to total biofilm removal and/or killing. Comparative analysis of the results obtained with colony biofilms and microtiter plate biofilms show that although extracellular polymeric substances and the biofilm structure are considered a determining factor in biofilm resistance, the ability of an antimicrobial agent to penetrate a biofilm is not correlated with its killing or removal efficiency. Also, the results reinforce the role of an appropriate antimicrobial selection as a key step in the design of disinfection processes for biofilm control. PMID:24773258
Araújo, Paula A; Mergulhăo, Filipe; Melo, Luís; Simőes, Manuel
Chemical composition and antimicrobial activity of Citrus essences on honeybee bacterial pathogen Paenibacillus larvae , the causal agent of American foulbrood
Antimicrobial properties and chemical composition of four citrus fruit essential oils to control Paenibacillus larvae, the causal agent of American foulbrood disease (AFB) were determined. This honeybee larvae disease occurs throughout the\\u000a world and is found in many beekeeping areas of Argentina. Citrus fruit essential oils tested were those from grapefruit (Citrus paradisi), sweet orange (Citrus sinensis), mandarin (Citrus nobilis)
Sandra R. Fuselli; Susana B. García de la Rosa; Martín J. Eguaras; Rosalía Fritz
Antimicrobial activity of flavonoids in medicinal plants from Tafí del Valle (Tucumán, Argentina).
Preliminary studies of flavonoids have been realised in five native species from Tafí del Valle (Tucumán, Argentina) used in popular medicine. Most of compounds detected were flavonoids mono and dihydroxylated in B ring. Screening for antimicrobial activity against Gram positive and Gram negative microorganisms has been realised with Lippia turbinata, Satureja parvifolia, Sambucus peruviana, Verbena officinalis and Chenopodium graveolens. The total extracts of flavonoids of each plant were tested and four species studied showed antimicrobial activity. PMID:11025172
Hernández, N E; Tereschuk, M L; Abdala, L R
Susceptibility of Legionella pneumophila to eight antimicrobial agents including four macrolides under different assay conditions.
A comparison of agar dilution and microdilution susceptibility testing for eight antimicrobial agents, including roxithromycin, was performed against 48 isolates of Legionella pneumophila. For agar dilution tests, charcoal free agar (BSYE) and charcoal supplemented agar (BCYE) were used. In general, BSYE agar produced lower MICs than BCYE agar, except for imipenem. Microdilution testing data fell between the data obtained for the two agar media. The MBCs were two to sixteen fold higher than the MICs. Prolongation of the incubation time from 48 h to 72 h or growth in 5% CO2 did not influence the results. As tested by the microdilution method, an increase in the inoculum from 10(5) to 10(7) was associated with a two-fold increase in the MIC. Roxithromycin and two other investigational macrolides (A-56268 and rosaramicin) demonstrated better in-vitro activity than erythromycin. PMID:2526110
Liebers, D M; Baltch, A L; Smith, R P; Hammer, M C; Conroy, J V
Effect of hyperbaric oxyhelium gas on response of bacteria to antimicrobial agents in vitro.
Modern diving techniques can require the treatment of infection in an atmosphere of pressurized oxyhelium gas. The antibiotic susceptibility of 16 species and strains (eight genera) of gram-negative bacilli and 3 species and strains (two genera) of gram-positive cocci to each of 21 antimicrobial agents was assessed in air at atmospheric pressure and in oxyhelium gas at an absolute pressure of 7 bar (ca. 709 kPa). A disk diffusion technique was employed, and significantly different results were obtained in the two atmospheres. The effect of oxyhelium on diameters of growth inhibition varied significantly with the bacterium and with the antibiotic and was particularly marked with certain bacterium-antibiotic combinations. The gram-negative bacilli generally gave reduced zone diameters in oxyhelium, whereas the gram-positive cocci showed a mixture of effects.
Kenward, M A; Alcock, S R; McKay, I C
Formation of complexes of antimicrobial agent norfloxacin with antitumor antibiotics of anthracycline series
NASA Astrophysics Data System (ADS)
The formation of complexes in solutions of the norfloxacin antimicrobial agent (NOR) with daunomycin (DAU) and nogalamycin (NOG), antitumor anthracycline antibiotics, was studied using 1H NMR spectroscopy. Based on the concentration and temperature dependences of the chemical shifts of the protons of interacting molecules, the equilibrium constants and thermodynamic parameters (enthalpy and entropy) of heteroassociation of the antibiotics were calculated. It was shown that NOR interacts with DAU (NOG) in aqueous solutions forming stacked heterocomplexes with parallel orientation of the molecular chromophores. The conclusion was drawn that such interactions should be taken into account when anthracyclines and quinolones are jointly administered during combined chemotherapy, since they can contribute to the medico-biological synergistic effect of these antibiotics.
Evstigneev, M. P.; Rybakova, K. A.; Davies, D. B.
Sparfloxacin-metal complexes as antifungal agents - Their synthesis, characterization and antimicrobial activities
NASA Astrophysics Data System (ADS)
Metal complexes with the third-generation quinolone antibacterial agent sparfloxacin (SPFX) or 5-amino-1-cyclopropyl-7-(cis-3,5-dimethyl-1-piperazinyl)-6,8,di-fluoro-1-4-dihydro-4-oxo-3-quinocarboxylic acid have been synthesized and characterized with physicochemical and spectroscopic techniques such as TLC, IR, NMR and elemental analyses. In these complexes, sparfloxacin acts as bidentate deprotonated ligands bound to the metal through the pyridone oxygen and one carboxylate oxygen. The antimicrobial activity of these complexes has been evaluated against four Gram-positive and seven Gram-negative bacteria. Antifungal activity against five different fungi has been evaluated and compared with reference drug sparfloxacin. Fe 2+-SPFX and Cd 2+-SPFX complexes showed remarkable potency as compared to the parent drug.
Sultana, Najma; Arayne, M. Saeed; Gul, Somia; Shamim, Sana
Synthesis and characterization of some hydroxypyridone derivatives and their evaluation as antimicrobial agents.
The synthesis, in vitro antimicrobial activities of some novel hydroxy pyridines supported with various pharmacophores is described. Twenty-six out of the tested 58 compounds exhibited variable inhibitory effects on the growth of the tested Gram positive and Gram negative bacteria. The tested compounds revealed better activity against the Gram positive rather than the Gram negative strains. The synthesized hydroxypyridones have shown very significant inhibitory effect against Staphylococcus aureus and Bacillus subtilis. Twelve compounds namely; 5d, 5f, 6a, 6b, 8b, 18b, 18c, 19c, 21d, 22b, 22d and 23d were able to produce appreciable growth inhibitory activity against Candida albicans when compared to Clotrimazole. Among these, 22d proved to be the most potent antifungal agent. PMID:22803670
Faidallah, Hassan M; Rostom, Sherif A F; Khan, Khalid A; Basaif, Salem A
In vitro activities of 47 antimicrobial agents against three Campylobacter spp. from pigs.
The in vitro activities of 47 antimicrobial agents against 30 isolates of Campylobacter species from pigs were determined by the agar dilution technique. The isolates were obtained from pigs with proliferative enteritis and included 10 strains each of Campylobacter coli, Campylobacter sputorum subsp. mucosalis, and "Campylobacter hyointestinalis Gebhart et al." (this name is not on the Approved Lists). Carbadox, furazolidone, nitrofurantoin, gentamicin, and dimetridazole were the most active drugs, inhibiting all three Campylobacter species with a MIC for 50% of the isolates of 2 micrograms/ml or less. Trimethoprim-sulfamethoxazole, cefazolin, sulfachloropyridazine, novobiocin, vancomycin, sulfathiazole, cyclohexamide, bacitracin, p-arsanilic acid, and colistin were the least active, with MICs for 50% of the isolates ranging from 16 to greater than or equal to 128 micrograms/ml. PMID:3985597
Gebhart, C J; Ward, G E; Kurtz, H J
Plants of Haiti used as antifertility agents.
Haitian empirical medicine sprang from both European (16th to 19th century) and African (especially voodoo) traditional therapies. The use of medicinal herbs is highly developed. Our purpose was to list the plants held to be antifertility agents in the island. We identified about twenty species more or less currently used by the women as abortifacients or emmenagogues. The chemistry and active components of a few species are well-known. However, for most of them, some were partially studied, and no relation could be established between their chemical composition and their potential activities, and the rest are chemically unknown. We chemically screened extracts of Casearia ilicifolia, Eleutherine bulbosa, Rhoeo spathacea and Stemodia durantifolia, and identified flavonoids, triterpenes and sterols in the leaves of C. ilicifolia, and naphthoquinones, and a new anthraquinone, anthracene-9,10-dione-1,5-diol-4-methoxy-3-methyl-2-carboxylic acid methyl ester, in the bulbs of E, bulbosa. R. spathacea showed a stimulative activity on mouse uterus. Antifertility screening tests of C. ilicifolia and E. bulbosa showed activity in rats, but also probably toxicity. PMID:7109665
Weniger, B; Haag-Berrurier, M; Anton, R
Ethnobotanical and antimicrobial studies of some plants used in Kibwezi (Kenya) for management of lower respiratory tract infections.
Respiratory tract infections have gained worldwide recognition especially due to the increased incidence of HIV/AIDS. The bacteria responsible for these infections have also become increasingly resistant to chemotherapeutic agents in lower respiratory infections in Kibwezi in Kenya. Interviews were conducted using semi-structured questionnaires and detailed discussions with respondents. During the field surveys direct observations were made on how these plants are used. From the ethnobotanical survey the modes of preparation used included chewing and boiling. The plant parts used were mostly bark and root, which implies that the main methods of harvesting these plants are destructive in nature. Water and methanolic extracts of the three most popular plants, Acacia nilotica, Strychnos heninngsii and Microglossa densiflora were tested against three test organism: Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli for their antimicrobial properties. The efficacy of the extracts was tested by bioassay method using the disk diffusion test. It was interesting to note that none of the tested water extracts showed any activity against the test organisms. This is despite the fact that about 83% of the local people used water for extraction. Methanolic extracts of Acacia nilotica and Strychnos heninningsii showed efficacy against S. aureus, S. pneumoniae and E. coli. The findings of this research indicate that A. nilotica and S. heninngsii have antimicrobial properties and further work especially using mammalian models is recommended. PMID:22238495
Kariuki, A C; Njoroge, G N
Plant storage proteins with antimicrobial activity: novel insights into plant defense mechanisms.
Storage proteins perform essential roles in plant survival, acting as molecular reserves important for plant growth and maintenance, as well as being involved in defense mechanisms by virtue of their properties as insecticidal and antimicrobial proteins. These proteins accumulate in storage vacuoles inside plant cells, and, in response to determined signals, they may be used by the different plant tissues in response to pathogen attack. To shed some light on these remarkable proteins with dual functions, storage proteins found in germinative tissues, such as seeds and kernels, and in vegetative tissues, such as tubercles and leaves, are extensively discussed here, along with the related mechanisms of protein expression. Among these proteins, we focus on 2S albumins, Kunitz proteinase inhibitors, plant lectins, glycine-rich proteins, vicilins, patatins, tarins, and ocatins. Finally, the potential use of these molecules in development of drugs to combat human and plant pathogens, contributing to the development of new biotechnology-based medications and products for agribusiness, is also presented. PMID:21746866
Cândido, Elizabete de Souza; Pinto, Michelle Flaviane Soares; Pelegrini, Patrícia Barbosa; Lima, Thais Bergamin; Silva, Osmar Nascimento; Pogue, Robert; Grossi-de-Sá, Maria Fátima; Franco, Octávio Luiz
Effect of extender supplementation with various antimicrobial agents on viability of Brucella ovis and Actinobacillus seminis in cryopreserved ovine semen.
The objective was to determine the effectiveness of various antimicrobial agents added to semen extender for inactivation of B. ovis or A. seminis in ovine semen after cryopreservation. In Experiment 1, 20 ejaculates from a crossbred ram infected with B. ovis were cryopreserved in Tris-based extenders with various antimicrobial agents: (I) control without antibiotics, (II) with penicillin and streptomycin (1000 IU/mL and 1 mg/mL, respectively), (III) lincomycin (0.15 mg/mL), (IV) sulphadiazine (0.60 mg/mL), and (V) gentamicin sulphate (0.25 mg/mL). Semen was stored in 0.25 mL straws at a final concentration of 150 × 10(6) spermatozoa/mL. After thawing (37 °C for 30 s), sperm total motility (TM), sperm morphology, integrity of sperm membranes, and bacterial growth were assessed. In Experiment 2, six B. ovis isolates were separately inoculated into aliquots of a fresh ejaculate from a B. ovis-free ram. Mock inoculated semen was processed for cryopreservation using the five extenders described above, and bacteriologically evaluated after thawing. In Experiment 3, sensitivity of A. seminis to the same antimicrobial agents was evaluated by inoculating an ejaculate from an A. seminis and B. ovis-free ram. There were no significant differences among treatments in post-thawing sperm parameters. B. ovis was isolated from 100% (20/20), 0% (0/20), 95% (19/20), 100% (20/20), and 5% (1/20) of semen samples diluted in tris-based extender of untreated (I) and treated semen samples with antimicrobial agents II, III, IV, and V, respectively. Frequencies of isolation from samples treated with antimicrobial agent II and V were significantly lower than untreated ones (P < 0.05). There were no significant differences in the profile of antimicrobial resistance of different B. ovis isolates. A. seminis had a similar sensitivity to the antimicrobial agents. We concluded that addition of a combination of penicillin and streptomycin or gentamicin alone to ram semen cryo-extenders inactivated B. ovis and A. seminis. PMID:20708246
Moustacas, V S; Xavier, M N; Carvalho-Júnior, C A; Costa, E A; Henry, M; Santos, R L
A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii)
William F. McDonald; Stacy C. Wright; Andrew C. Taylor
Essential oils and herbal extracts as antimicrobial agents in cosmetic emulsion.
The cosmetic industry adapts to the needs of consumers seeking to limit the use of preservatives and develop of preservative-free or self-preserving cosmetics, where preservatives are replaced by raw materials of plant origin. The aim of study was a comparison of the antimicrobial activity of extracts (Matricaria chamomilla, Aloe vera, Calendula officinalis) and essential oils (Lavandulla officinallis, Melaleuca alternifolia, Cinnamomum zeylanicum) with methylparaben. Extracts (2.5 %), essential oils (2.5 %) and methylparaben (0.4 %) were tested against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, Candida albicans ATCC 14053. Essentials oils showed higher inhibitory activity against tested microorganism strain than extracts and methylparaben. Depending on tested microorganism strain, all tested extracts and essential oils show antimicrobial activity 0.8-1.7 and 1-3.5 times stronger than methylparaben, respectively. This shows that tested extracts and essential oils could replace use of methylparaben, at the same time giving a guarantee of microbiological purity of the cosmetic under its use and storage. PMID:24426114
Herman, Anna; Herman, Andrzej Przemys?aw; Domagalska, Beata Wanda; M?ynarczyk, Andrzej
A review of the comparative in-vitro activities of 12 antimicrobial agents, with a focus on five new 'respiratory quinolones
The efficacies of many antimicrobial agents are being threatened by a global increase in the numbers of resistant bacterial pathogens—microorganisms that were once susceptible to some of these agents. In particular, antimicrobial resistance amongst strains of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae has limited the usefulness of first-line agents in some clinical settings. Quinolones were introduced in the 1980s
Joseph M. Blondeau
Therapeutic Potential of Plants as Anti-microbials for Drug Discovery
The uses of traditional medicinal plants for primary health care have steadily increased worldwide in recent years. Scientists are in search of new phytochemicals that could be developed as useful anti-microbials for treatment of infectious diseases. Currently, out of 80% of pharmaceuticals derived from plants, very few are now being used as anti-microbials. Plants are rich in a wide variety of secondary metabolites that have found anti-microbial properties. This review highlights the current status of traditional medicine, its contribution to modern medicine, recent trends in the evaluation of anti-microbials with a special emphasis upon some tribal medicine, in vitro and in vivo experimental design for screening, and therapeutic efficacy in safety and human clinical trails for commercial outlet. Many of these commercially available compounds are crude preparations administered without performing human clinical trials. Recent methods are useful to standardize the extraction for scientific investigation of new phytochemicals and anti-microbials of traditionally used plants. It is concluded that once the local ethnomedical preparations of traditional sources are scientifically evaluated before dispensing they should replace existing drugs commonly used for the therapeutic treatment of infection. This method should be put into practice for future investigations in the field of ethnopharmacology, phytochemistry, ethnobotany and other biological fields for drug discovery.
Perumal Samy, Ramar
Derivatives of the Antimicrobial Peptide BP100 for Expression in Plant Systems
Production of antimicrobial peptides in plants constitutes an approach for obtaining them in high amounts. However, their heterologous expression in a practical and efficient manner demands some structural requirements such as a minimum size, the incorporation of retention signals to assure their accumulation in specific tissues, and the presence of protease cleavage amino acids and of target sequences to facilitate peptide detection. Since any sequence modification may influence the biological activity, peptides that will be obtained from the expression must be screened prior to the synthesis of the genes for plant transformation. We report herein a strategy for the modification of the antimicrobial undecapeptide BP100 that allowed the identification of analogues that can be expressed in plants and exhibit optimum biological properties. We prepared 40 analogues obtained by incorporating repeated units of the antimicrobial undecapeptide, fragments of natural peptides, one or two AGPA hinges, a Gly or Ser residue at the N-terminus, and a KDEL fragment and/or the epitope tag54 at the C-terminus. Their antimicrobial, hemolytic and phytotoxic activities, and protease susceptibility were evaluated. Best sequences contained a magainin fragment linked to the antimicrobial undecapeptide through an AGPA hinge. Moreover, since the presence of a KDEL unit or of tag54 did not influence significantly the biological activity, these moieties can be introduced when designing compounds to be retained in the endoplasmic reticulum and detected using a complementary epitope. These findings may contribute to the design of peptides to be expressed in plants.
Badosa, Esther; Moiset, Gemma; Montesinos, Laura; Talleda, Montserrat; Bardaji, Eduard; Feliu, Lidia; Planas, Marta; Montesinos, Emilio
['In vitro' activity of different antimicrobial agents on Gram-negative nonfermentative bacilli, excluding Pseudomonas aeruginosa and Acinetobacter spp].
Gram-negative nonfermentative bacilli (NFB) are widely spread in the environment. Besides of difficulties for identification, they often have a marked multiresistance to antimicrobial agents, including those active against Pseudomonas aeruginosa. The objective of this study was to evaluate the 'in vitro' activity of different antimicrobial agents on 177 gram-negative nonfermentative bacilli isolates (excluding Pseudomonas aeruginosa and Acinetobacter spp.) isolated from clinical specimens. Minimum inhibitory concentrations (MIC) were determined according to the Mueller Hinton agar dilution method against the following antibacterial agents: ampicillin, piperacillin, piperacillin-tazobactam, sulbactam, cefoperazone, cefoperazone-sulbactam, ceftazidime, cefepime, aztreonam, imipenem, meropenem, colistin, gentamicin, amikacin, trimethoprim-sulfamethoxazole, chloramphenicol, erythromycin, rifampin, norfloxacin, ciprofloxacin and minocycline. Seven isolates: Sphingobacterium multivorum (2), Sphingobacteriumspiritivorum (1), Empedobacterbrevis (1), Weeksella virosa (1), Bergeyella zoohelcum (1) and Oligella urethralis (1), were tested for amoxicillin-clavulanic acid and ampicillin-sulbactam susceptibility, and susceptibility to cefoperazone or sulbactam was not determined. Multiresistance was generally found in Stenotrophomonas maltophilia, Burkholderia cepacia, Chryseobacterium spp., Myroides spp., Achromobacter xylosoxidans, and Ochrobactrum anthropi isolates. On the other hand, Pseudomonas stutzeri, Shewanella putrefaciens-algae, Sphingomonas paucimobilis, and Pseudomonas oryzihabitans, Bergeyella zoohelcum, Weeksella virosa and Oligella urethralis were widely susceptible to the antibacterial agents tested. As a result of the wide variation in antimicrobial susceptibility shown by different species, a test on susceptibility to different antibacterial agents is essential in order to select an adequate therapy. The marked multiresistance evidenced by some species, prompts the need to develop new antimicrobial agents active against this group of bacteria and to search for synergistic combinations. PMID:15991478
Vay, C A; Almuzara, M N; Rodríguez, C H; Pugliese, M L; Lorenzo Barba, F; Mattera, J C; Famiglietti, A M R
Synergistic inhibitory effect of cationic peptides and antimicrobial agents on the growth of oral streptococci.
Although chlorhexidine is one of the most efficacious antimicrobial agents used for the prevention of dental caries, side effects limit its application. The effects of gaegurin 6 (GGN6), an animal-derived cationic peptide, and its derivatives PTP6 and PTP12 on the growth of oral streptococci were investigated to assess the potential of these agents for use in the prevention of dental caries. The minimal inhibitory concentrations of the peptides for inhibition of the growth of oral streptococci (Streptococcus mutans , S. sobrinus, S. sanguis and S. gordonii) ranged from 1.2 to 8.2 muM. The peptides also exhibited marked synergistic antibacterial effects with chlorhexidine or xylitol. The most effective combinations (fractional inhibitory concentration index of 0.5) were xylitol with GGN6 against S. gordonii 10558 and chlorhexidine with either GGN6 or PTP6 against S. sobrinus OMZ-175. These results indicate that cationic peptides alone or in combination with chlorhexidine or xylitol might prove effective for the inhibition of the growth of cariogenic oral streptococci in situ. PMID:14571120
Kim, Sukwon S; Kim, Sunkyu; Kim, Eunshin; Hyun, Byungkuk; Kim, Kack-Kyun; Lee, Byeong Jae
Susceptibility of bacterial etiological agents to commonly-used antimicrobial agents in children with sepsis at the Tamale Teaching Hospital
Background Bloodstream infections in neonates and infants are life-threatening emergencies. Identification of the common bacteria causing such infections and their susceptibility patterns will provide necessary information for timely intervention. This study is aimed at determining the susceptibilities of bacterial etiological agents to commonly-used antimicrobial agents for empirical treatment of suspected bacterial septicaemia in children. Methods This is a hospital based retrospective analysis of blood cultures from infants to children up to 14 years of age with preliminary diagnosis of sepsis and admitted to the Neonatal Intensive Care Unit (NICU) and Paediatric Wards of the Teaching Hospital Tamale from July 2011 to January 2012. Results Out of 331 blood specimens cultured, the prevalence of confirmed bacterial sepsis was 25.9% (86/331). Point prevalence for confirmed cases from NICU was 44.4% (28/63) and 21.6% (58/268) from the Paediatric ward. Gram positive cocci (GPC) were the predominant isolates with Coagulase positive (32.2%) and Coagulase-negative (28.7%) Staphylococci accounting for 60.9% of the total isolates. Gram negative rods (GNR) comprised 39.1% of all isolates with Klebsiella, E.coli and Salmonella being the most common organisms isolated. Klebsiella was the most frequent GNR from the NICU and Salmonella typhi was predominantly isolated from the paediatric ward. Acinetobacter showed 100.0% susceptibility to Ceftriaxone and Cefotaxime but was resistant (100.0%) to Ampicillin, Tetracycline and Cotrimoxazole. Escherichia coli and Klebsiella were 80.0% and 91.0% susceptible to Ceftriaxone and Cefotaxime respectively. Klebsiella species showed 8.3% susceptibility to Tetracycline but was resistant to Ampicillin and Cotrimoxazole. Escherichia coli showed 40.0% susceptibility to Ampicillin, Chloramphenicol and Cotrimoxazole; 20.0% susceptibility to Tetracycline and 80.0% susceptible to Gentamicin and Cefuroxime. Coagulase negative Staphylococci was susceptible to Gentamicin (72.0%) but Coagulase positive Staphylococci showed intermediate sensitivity to Gentamicin (42.9%). Conclusion Coagulase Negative, Coagulase Positive Staphylococci, Salmonella and Klebsiella were the aetiological agents of bloodstream infection among children at TTH. While gram-positive and gram-negative bacteria showed low susceptibility to Ampicillin, Tetracycline and Cotrimoxazole, the GNR were susceptible to Gentamicin and third-generation cephalosporins.
Obesity is associated with a number of serious health consequences, including type 2 diabetes, cardiovascular disease and a variety of cancers among others and has been repeatedly shown to be associated with a higher risk of mortality. The relatively recent discovery that the composition and metabolic activity of the gut microbiota may affect the risk of developing obesity and related disorders has led to an explosion of interest in this distinct research field. A corollary of these findings would suggest that modulation of gut microbial populations can have beneficial effects with respect to controlling obesity. In this addendum, we summarize our recent data, showing that therapeutic manipulation of the microbiota using different antimicrobial strategies may be a useful approach for the management of obesity and metabolic conditions. In addition, we will explore some of the mechanisms that may contribute to microbiota-induced susceptibility to obesity and metabolic diseases.
Murphy, Eileen F.; Clarke, Siobhan F.; Marques, Tatiana M.; Hill, Colin; Stanton, Catherine; Ross, R. Paul; O'Doherty, Robert M.; Shanahan, Fergus; Cotter, Paul D.
Drug-induced liver injury due to antimicrobials, central nervous system agents, and nonsteroidal anti-inflammatory drugs.
Antimicrobial agents including antituberculosis (anti-TB) agents are the most common cause of idiosyncratic drug-induced liver injury (DILI) and drug-induced liver failure across the world. Better molecular and genetic biomarkers are acutely needed to help identify those at risk of liver injury particularly for those needing antituberculosis therapy. Some antibiotics such as amoxicillin-clavulanate and isoniazid consistently top the lists of agents in retrospective and prospective DILI databases. Central nervous system agents, particularly antiepileptics, account for the second most common class of agents implicated in DILI registries. Hepatotoxicity from older antiepileptics such as carbamazepine, phenytoin, and phenobarbital are often associated with hypersensitivity features, whereas newer antiepileptic drugs have a more favorable safety profile. Antidepressants and nonsteroidal anti-inflammatory drugs carry very low risk of significant liver injury, but their prolific use make them important causes of DILI. Early diagnosis and withdrawal of the offending agent remain the mainstays of minimizing hepatotoxicity. PMID:24879980
Devarbhavi, Harshad; Andrade, Raúl J
Antimicrobial activity of plant extract Ankaferd Blood Stopper.
The in vitro antimicrobial activity of Ankaferd Blood Stopper (ABS) was assessed on 102 clinical isolates from both Gram negative and Gram positive bacteria and four standard strains, including MRSA ATCC 43300, MSSA ATCC 25923, P. aeruginosa ATCC 27853 and E. coli ATCC 35218. ABS was significantly active against all bacteria investigated. PMID:18930120
Tasdelen Fisgin, Nuriye; Tanriverdi Cayci, Yeliz; Coban, Ahmet Yilmaz; Ozatli, Duzgun; Tanyel, Esra; Durupinar, Belma; Tulek, Necla
Stable coexistence of an invasive plant and biocontrol agent: a parameterized coupled plant-herbivore model
Summary 1. Coupled plant-herbivore models, allowing feedback from plant to herbivore popu- lations and vice versa, enable us to predict the impact of biocontrol agents on their target weed populations; however, they are rarely used in biocontrol studies. We describe the population biology of the invasive plant Echium plantagineum and the weevil Mogulones larvatus , a biocontrol agent, in Australia.
In vitro antimicrobial activity of Romanian medicinal plants hydroalcoholic extracts on planktonic and adhered cells.
The aim of this study was to assess the antibacterial and antifungal potential of some Romanian medicinal plants, arnica--Arnica montana, wormwood--Artemisia absinthium and nettle--Urtica dioica. In order to perform this antimicrobial screening, we obtained the vegetal extracts and we tested them on a series of Gram-positive and Gram-negative bacteria, and also against two fungal strains. The vegetal extracts showed antimicrobial activity preferentially directed against the planktonic fungal and bacterial growth, while the effect against biofilm formation and development was demonstrated only against S. aureus and C. albicans. Our in vitro assays indicate that the studied plant extracts are a significant source of natural alternatives to antimicrobial therapy, thus avoiding antibiotic therapy, the use of which has become excessive in recent years. PMID:21717806
Stanciuc, A M; Gaspar, A; Moldovan, L; Saviuc, C; Popa, M; M?ru?escu, L
Use of genetically engineered phage to deliver antimicrobial agents to bacteria: an alternative therapy for treatment of bacterial infections.
The emergence and increasing prevalence of multidrug-resistant bacterial pathogens emphasizes the need for new and innovative antimicrobial strategies. Lytic phages, which kill their host following amplification and release of progeny phage into the environment, may offer an alternative strategy for combating bacterial infections. In this study, however, we describe the use of a nonlytic phage to specifically target and deliver DNA encoding bactericidal proteins to bacteria. To test the concept of using phage as a lethal-agent delivery vehicle, we used the M13 phagemid system and the addiction toxins Gef and ChpBK. Phage delivery of lethal-agent phagemids reduced target bacterial numbers by several orders of magnitude in vitro and in a bacteremic mouse model of infection. Given the powerful genetic engineering tools available and the present knowledge in phage biology, this technology may have potential use in antimicrobial therapies and DNA vaccine development. PMID:12654662
Westwater, Caroline; Kasman, Laura M; Schofield, David A; Werner, Phillip A; Dolan, Joseph W; Schmidt, Michael G; Norris, James S
The Antimicrobial Properties of Cedar Leaf (Thuja plicata) Oil; A Safe and Efficient Decontamination Agent for Buildings
Cedar leaf oil (CLO), derived from the Western red cedar, Thuja plicata, was evaluated as a safe and acceptable broad spectrum antimicrobial agent, with a view to its potential applications in buildings, including the alleviation of sick building syndrome. Various Gram-positive and Gram-negative human bacteria, and two fungal organisms, all known to be common environmental sources of potential infection, were selected and tested quantitatively, and all of them were found to be susceptible to CLO liquid and vapor. Bacterial spores and Aspergillus niger were sensitive, although less so than the vegetative bacteria. Similar tests with cultured human lung cells showed that continuous exposure to CLO vapor for at least 60 minutes was not toxic to the cells. Based on these results, CLO shows promise as a prospective safe, green, broad-spectrum anti-microbial agent for decontamination of buildings.
Hudson, James; Kuo, Michael; Vimalanathan, Selvarani
Comparison of the antimicrobial effect of heavy silicone oil and conventional silicone oil against endophthalmitis-causing agents
Purpose: To conduct an in vitro experimental study comparing the effectiveness of conventional silicone oil and heavy silicone oil against endophthalmitis-causing agents. Materials and Methods: The antimicrobial activity of conventional silicone oil (RS OIL 5000) and heavy silicone oil (heavySil 1500) was tested. The antimicrobial effects of both silicone oils were determined by the growing capability of the microorganism. Results: The number of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans decreased to zero levels at the second day of inoculation in heavy silicone oil. In conventional silicone oil, the microorganisms survived longer than in heavy silicone oil. Conclusion: Heavy silicone oil seems to be more effective than conventional silicone oil against endophthalmitis-causing agents.
Ornek, Nurgul; Apan, Teoman; Ogurel, Reyhan; Ornek, Kemal
The continuing search for antitumor agents from higher plants
Plant secondary metabolites and their semi-synthetic derivatives continue to play an important role in anticancer drug therapy. In this short review, selected single chemical entity antineoplastic agents from higher plants that are currently in clinical trials as cancer chemotherapy drug candidates are described. These compounds are representative of a wide structural diversity. In addition, the approaches taken toward the discovery of anticancer agents from tropical plants in the laboratory of the authors are summarized. The successful clinical utilization of cancer chemotherapeutic agents from higher plants has been evident for about half a century, and, when considered with the promising pipeline of new plant-derived compounds now in clinical trials, this augurs well for the continuation of drug discovery research efforts to elucidate additional candidate substances of this type.
Pan, Li; Chai, Heebyung; Kinghorn, A. Douglas
Antimicrobial and antioxidant activities of two endemic plants from Aksaray in Turkey.
This study was designed to examine the in vitro antimicrobial and antioxidant activities of the methanol, ethanol, water, n-hexane and dicholoromethane extracts of two Allium species (Allium scabriflorum and Allium tchihatschewii) which are endemic for the flora of Turkey. The antimicrobial efficiency of the plant was evaluated according to disc diffusion and microdilution broth methods. The antimicrobial test results showed that the extracts of A. scabriflorum and A. tchihatschewii showed varying degrees of antimicrobial activity on the tested microorganisms. The extracts were screened for their possible antioxidant activities by three complementary tests; DPPH free radical-scavenging, scavenging of hydrogen peroxide and metal chelating activity assays. All the extracts of A. scabriflorum and A. tchihatschewii exhibited lower DPPH free radical scavenging activity but higher metal chelating activity when compared to standards. The values of scavenging of hydrogen peroxide of the extracts were higher than the standards that of ?-tocopherol, BHA, BHT and trolox, but close to that of ascorbic acid. In addition to the antioxidant activity of these plants, the total phenolic compounds and flavonoids were also measured in the extracts. The results presented here may suggest that the extracts of A. scabriflorum and A. tchihatschewii possess antimicrobial and antioxidant properties, and therefore, they can be used as a natural preservative ingredient in food and/or pharmaceutical industry. PMID:24146474
Ozusaglam, Meltem Asan; Darilmaz, Derya Onal; Erzengin, Mahmut; Teksen, Mehtap; Erkul, Seher Karaman
Killing of the Yeast and Hyphal Forms of Candida albicans Using a Light-Activated Antimicrobial Agent
. Oral infections due to Candida albicans are a common occurrence in patients with acquired immunodeficiency syndrome (AIDS). The purpose of this investigation was\\u000a to determine whether the yeast and hyphal forms of the organism could be killed using the light-activated antimicrobial agent\\u000a toluidine blue O (TBO). Three variables were investigated: TBO concentration, laser light dose and pre-irradiation time (PIT).
Z. Jackson; S. Meghji; A. MacRobert; B. Henderson; M. Wilson
Activity of Selected Antimicrobial Agents Against Strains of Staphylococcus aureus Isolated from Bovine Intramammary Infections that Produce ?-Lactamase
The activity of selected antimicrobial agents was determined against strains of Staphylococcus aureus that were isolated from bovine intramammary infec- tions and that were positive or negative for b- lactamase. A total of 107 S. aureus strains (70 that were positive for b-lactamase and 37 that were nega- tive for b-lactamase) were used in the study. Produc- tion of b-lactamase
Jeffrey L. Watts; Sarah A. Salmon
Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.
The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar.
Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H
[The implementation of the broth microdilution method to determine bacterial susceptibility to antimicrobial agents].
The determination of quantitative data (minimal inhibitory concentrations [MIC values]) using the broth microdilution method is considered the method of choice for in-vitro susceptibility testing of bacterial pathogens. For the inoculation of microtiter plates used in the broth microdilution method, an inoculation density of 5x10(5) CFU/ml has to be achieved according to the CLSI standard. In this study, it was shown that the requested CFU/ml corresponded to an optical density of 0.00027 of a bacterial suspension determined in a spectrophotometer at 625 nm (OD625). The comparison of susceptibility data of clinical isolates determined by agar disk diffusion and, in parallel, by broth microdilution confirmed the comparability of both methods. For most antibiotics the frequency of "very major errors" was below 10%. However, a higher frequency of errors was observed for combinations of antimicrobial agents and bacteria for which no valid breakpoints are available. The comparative testing of cephalothin showed a frequency of"very major errors" of 20.3% for staphylococci and 18.4% for Enterobacteriaceae; for apramycin the frequency of "major errors"was found to be 46.0% for Enterobacteriaceae. The reference strains as recommended in the CLSI Standard M31-S1 should be used for quality assurance. PMID:17290942
Rocksin, Anja; Gerlach, Gerald-Friedrich; Schwarz, Stefan
The nitrosation of hexetidine and hexedine: characterization of the major nitrosamine from common antimicrobial agents.
The acidic nitrosation of hexetidine and hexedine, common antimicrobial agents and drug constituents, leads to a mixture of nitrosamines. The major nitrosamine product, "HEXNO", forms rapidly in yields as high as 60% over the pH range 1-4.8 at incubation times of 1 h at 37 degrees C with 40 mM NO2- and 10 mM hexetidine. On the basis of extensive spectroscopic characterization and independent synthesis HEXNO has been assigned the structure of 1-(2-ethylhexyl)-3-nitroso-4-methyl-4-[[N-(2-ethylhexyl)-N- nitrosoamino]methyl]imidazolidine (7). The synthesis of HEXNO involves the novel interception by potassium nitrite in ether/18-crown-6 of an imminium ion produced from the reaction of hexedine with benzyl chloroformate. Collapse of the alpha-amino nitrous ester produced by this reaction yields the nitrosamine containing carbamate 8, which yields HEXNO after removal of the carbamate with trimethylsilyl iodide and subsequent nitrosation. The rapid formation of HEXNO from hexetidine and hexedine supports the hypothesis that tertiary geminal diamines will produce nitrosamines rapidly by a mechanism which involves the cleavage of a nitrosammonium ion with the assistance of the neighboring nitrogen atom. This process is deemed to be of possible importance in the endogenous production of potentially carcinogenic nitrosamines because of its low nitrite requirement and high nitrosation rate. The available data suggest the probable formation of HEXNO and other nitrosamines from hexetidine under conditions of its use. PMID:7696545
Bae, J Y; Mende, P; Shevlin, G; Spiegelhalder, B; Preussmann, R; Loeppky, R N
Antibacterial agents and cystic fibrosis: synthesis and antimicrobial evaluation of a series of N-thiomethylazetidinones.
The increasing emergence of multidrug-resistant microorganisms is one of the greatest challenges in the clinical management of infectious disease. New antimicrobial agents are therefore urgently required, particularly in the treatment of chronic and recurrent infections often associated with antibiotic-resistant pathogens, as in the case of cystic fibrosis (CF) patients. This study reports the antibacterial activity of a series of monocyclic ?-lactams with an alkylidenecarboxyl chain or electron-withdrawing groups such as 4-OAc, 4-SAc, and 4-SO(2)Ph at the C4 position of the ring. N-Unsubstituted and N-thiomethyl derivatives were compared. A total of 33 azetidinones were tested for their activity against Gram-positive and Gram-negative bacterial clinical isolates. The combination of an N-thiomethyl group and a benzyl ester on the 4-alkylidene side chain were found to increase the potency against Gram-positive bacteria. The N-thiomethyl group clearly elevated the activity of 4-acetoxyazetidinones relative to the corresponding NH derivatives. The most active compounds showed minimum inhibitory concentration (MIC) values of 4 and 8 mg L(-1) against methicillin-resistant Staphylococcus aureus isolated from pediatric patients with CF. PMID:21834093
Galletti, Paola; Cocuzza, Clementina E A; Pori, Matteo; Quintavalla, Arianna; Musumeci, Rosario; Giacomini, Daria
Effects of Antimicrobial Agents on the Milky Disease Bacteria Bacillus popilliae and Bacillus lentimorbus1
The effects of antibiotics, sulfonamides, and other antimicrobial agents on vegetative cultures of five strains of milky disease bacteria were compared with those on Bacillus subtilis Cohn emend. Prazmowski, Staphylococcus aureus Rosenbach, Sarcina lutea Schroeter, Escherichia coli (Migula) Castellani and Chalmers, Saccharomyces pastorianus Hansen, and Mucor ramannianus Moel. Similar numbers of viable cells of each organism were exposed to the test materials by use of an antibiotic-sensitivity disc method adapted from techniques recommended by the Food and Drug Administration in the Federal Register. The results suggest that vancomycin or ristocetin, as well as a few other materials, might be useful in controlling contamination either during culture of the fastidious milky disease bacteria or in large populations of vegetative cells undergoing treatment to induce sporulation. Inhibitory concentrations of vancomycin and ristocetin in shaken-tube tests were much lower than expected in comparison with results of sensitivity-disc tests on the milky disease bacteria. Sublethal concentrations of the two antibiotics elicited some morphological change in the bacteria.
Pridham, T. G.; Hall, H. H.; Jackson, R. W.
Synthesis and Biological Evaluation of 2-Aminobenzamide Derivatives as Antimicrobial Agents: Opening/Closing Pharmacophore Site
A series of new 2-aminobenzamide derivatives (1–10) has been synthesized in good to excellent yields by adopting both conventional and/or a time-efficient microwave assisted methodologies starting from isatoic anhydride (ISA) and characterized on the basis of their physical, spectral and microanalytical data. Selected compounds of this series were then tested against various bacterial (Bacillus subtilis (RCMB 000107) and Staphylococcus aureus (RCMB 000106). Pseudomonas aeruginosa (RCMB 000102) and Escherichia coli (RCMB 000103) and fungal strains (Saccharomyces cerevisiae (RCMB 006002), Aspergillus fumigatus (RCMB 002003) and Candida albicans (RCMB 005002) to explore their potential as antimicrobial agents. Compound 5 was found to be the most active compound among those tested, which showed excellent antifungal activity against Aspergillus fumigatus (RCMB 002003) more potent than standard Clotrimazole, and moderate to good antibacterial and antifungal activity against most of the other strains of bacteria and fungi. Furthermore, potential pharmacophore sites were identified and their activity was related with the structures in the solution.
Mabkhot, Yahia N.; Al-Majid, Abdullah M.; Barakat, Assem; Al-Showiman, Salim S.; Al-Har, Munirah S.; Radi, Smaail; Naseer, Muhammad Moazzam; Hadda, Taibi B.
NASA Astrophysics Data System (ADS)
The use of antimicrobials is a common practice for preservation of foods. Incorporation, in a food recipe, of chemical antimicrobials towards inhibition of spoilage and pathogenic micro-organisms results in the compositional modification of food. This treatment is nowadays undesirable for the consumer, who likes natural products. Scientific community reflecting consumers demand for natural antimicrobials has made efforts to investigate the possibility to use natural antimicrobials such us bacteriocins and essential oils of plant origin to inhibit microbial growth.
Drosinos, Eleftherios H.; Skandamis, Panagiotis N.; Mataragas, Marios
Plant Derived Antimalarial Agents: New Leads and Challenges
New treatments for malaria are urgently needed due to the increasing problem of drug-resistance in malaria parasites. The long-established use of quinine and the more recent introduction of artemisinin and its derivatives as highly effective antimalarials demonstrates that plant species are an important resource for the discovery of new antimalarial agents. Furthermore, many plant species continue to be used in
Colin W. Wright
Antioxidant, antimicrobial and cytotoxic activities of selected medicinal plants from Yemen
Ninety crude extracts, including dichloromethane, methanol and aqueous extracts from 30 medicinal plants used in the Yemeni ethnomedicine to treat common infections, were screened in vitro for antimicrobial activities against three Gram-positive bacteria and two Gram-negative bacteria, Candida maltosa and five opportunistic human fungal pathogens (two yeasts, three hyphomycetes).Most of the plants showed antibacterial activities. Extracts from Tamarindus indica flowers
Mohamed Al-Fatimi; Martina Wurster; Gudrun Schröder; Ulrike Lindequist
Diversity and Antimicrobial and Plant-Growth-Promoting Activities of Endophytic Fungi in Dendrobium loddigesii Rolfe
Endophytic fungi are ubiquitously distributed in orchids and have a great impact on the host plant. The diversity of endophytic\\u000a fungi in the medicinal orchid Dendrobium loddigesii Rolfe was investigated and their bioactivities in microbe and plant growth were explored here. Endophytic fungi were identified\\u000a by using morphological and molecular biological methods. Antimicrobial activity was determined by a standard disk
Xiao Mei Chen; Hai Ling Dong; Ke Xing Hu; Zhi Rong Sun; Juan Chen; Shun Xing Guo
Antimicrobial activity of some coumarin containing herbal plants growing in Finland
Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia
Tiina Ojala; Susanna Remes; Pasi Haansuu; Heikki Vuorela; Raimo Hiltunen; Kielo Haahtela; Pia Vuorela
Synergism between plant extract and antimicrobial drugs used on Staphylococcus aureus diseases.
Searches for substances with antimicrobial activity are frequent, and medicinal plants have been considered interesting by some researchers since they are frequently used in popular medicine as remedies for many infectious diseases. The aim of this study was to verify the synergism between 13 antimicrobial drugs and 8 plant extracts--"guaco" (Mikania glomerata), guava (Psidium guajava), clove (Syzygium aromaticum), garlic (Allium sativum), lemongrass (Cymbopogon citratus), ginger (Zingiber officinale), "carqueja" (Baccharis trimera), and mint (Mentha piperita)--against Staphylococcus aureus strains, and for this purpose, the disk method was the antimicrobial susceptibility test performed. Petri dishes were prepared with or without dilution of plant extracts at sub-inhibitory concentrations in Mueller-Hinton Agar (MHA), and the inhibitory zones were recorded in millimeters. In vitro anti-Staphylococcus aureus activities of the extracts were confirmed, and synergism was verified for all the extracts; clove, guava, and lemongrass presented the highest synergism rate with antimicrobial drugs, while ginger and garlic showed limited synergistic capacity. PMID:16951808
Betoni, Joyce Elaine Cristina; Mantovani, Rebeca Passarelli; Barbosa, Lidiane Nunes; Di Stasi, Luiz Claudio; Fernandes Junior, Ary
Principles of Judicious Use of Antimicrobial Agents for Pediatric Uppe r Respiratory Tract Infections
ABSTRACT. This article introduces a set of principles to define judicious antimicrobial use for five conditions that account for the majority of outpatient antimicrobial use in the United States. Data from the National Center for Health Statistics indicate that in recent years, approx- imately three fourths of all outpatient antibiotics have been prescribed for otitis media, sinusitis, bronchitis, pharyngitis, or
Scott F. Dowell; S. Michael Marcy; William R. Phillips; Michael A. Gerber; Benjamin Schwartz
Evaluation of new antimicrobial agents on Bacillus spp. strains: docking affinity and in vitro inhibition of glutamate-racemase.
Three glutamic acid derivatives, two boron-containing and one imide-containing compound, were synthesized and tested for antimicrobial activity targeting glutamate-racemase. Antimicrobial effect was evaluated over Bacillus spp. Docking analysis shown that the test compounds bind near the active site of racemase isoforms, suggesting an allosteric effect. The boron derivatives had greater affinity than the imide derivative. In vitro assays shown good antimicrobial activity for the boron-containing compounds, and no effectiveness for the imide-containing compounds. The minimum inhibitory concentration of tetracycline, used as standard, was lower than that of the boron-containing derivatives. However, it seems that the boron-containing derivatives are more selective for bacteria. Experimental evidence suggests that the boron-containing derivatives act by inhibiting the racemase enzyme. Therefore, these test compounds probably impede the formation of the bacterial cell wall. Thus, the boron-containing glutamic acid derivatives should certainly be of interest for future studies as antimicrobial agents for Bacillus spp. PMID:22871135
Tamay-Cach, Feliciano; Correa-Basurto, José; Villa-Tanaca, Lourdes; Mancilla-Percino, Teresa; Juárez-Montiel, Margarita; Trujillo-Ferrara, José G
Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens.
Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source. PMID:22691487
Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C
Screening of some Indian medicinal plants for their antimicrobial properties
A total of 82 Indian medicinal plants traditionally used in medicines were subjected to preliminary antibacterial screening against several pathogenic and opportunistic microorganisms. Aqueous, hexane and alcoholic extracts of each plant were tested for their antibacterial activity using agar well diffusion method at sample concentration of 200 mg\\/ml. The results indicated that out of 82 plants, 56 exhibited antibacterial activity
Iqbal Ahmad; Zafar Mehmood; Faiz Mohammad
The use of versatile plant antimicrobial peptides in agribusiness and human health.
Plant immune responses involve a wide diversity of physiological reactions that are induced by the recognition of pathogens, such as hypersensitive responses, cell wall modifications, and the synthesis of antimicrobial molecules including antimicrobial peptides (AMPs). These proteinaceous molecules have been widely studied, presenting peculiar characteristics such as conserved domains and a conserved disulfide bond pattern. Currently, many AMP classes with diverse modes of action are known, having been isolated from a large number of organisms. Plant AMPs comprise an interesting source of studies nowadays, and among these there are reports of different classes, including defensins, albumins, cyclotides, snakins and several others. These peptides have been widely used in works that pursue human disease control, including nosocomial infections, as well as for agricultural purposes. In this context, this review will focus on the relevance of the structural-function relations of AMPs derived from plants and their proper use in applications for human health and agribusiness. PMID:24548568
de Souza Cândido, Elizabete; e Silva Cardoso, Marlon Henrique; Sousa, Daniel Amaro; Viana, Juliane Cançado; de Oliveira-Júnior, Nelson Gomes; Miranda, Vívian; Franco, Octávio Luiz
[Antimicrobial and rapid bactericidal activities of sitafloxacin and other agents against Streptococcus pyogenes].
We evaluated the in vitro activity of sitafloxacin against Japanese clinical isolates of Streptococcus pyogenes by broth microdilution susceptibility testing and time-kill studies to elucidate its eradication potential against S. pyogenes. One hundred and nineteen clinical isolates of S. pyogenes isolated from pharynx were tested to sitafloxacin and seven other agents in the susceptibility testing. The time-kill studies were conducted with five strains, one of which was resistant to clarithromycin, one resistant to levofloxacin and one type strain of S. pyogenes. In the time-kill studies, sitafloxacin, garenoxacin, amoxicillin and clarithromycin were assessed at static concentrations of their respective peak concentrations in plasma (C(max)) when administered as oral single doses for adult patients with S. pyogenes infections. We found the rank order of antimicrobial activity against S. pyogenes isolates was: cefcapene (MIC90, 0.015 microg/mL) > amoxicillin (0.03 microg/mL) > sitafloxacin (0.12 microg/mL) > garenoxacin (0.25 microg/mL) > levofloxacin (4 microg/mL) > minocycline (16 microg/mL). Macrolide-resistant isolates accounted for 72 (60.5%), resulting in clarithromycin and azithromycin MIC90s of > 32 and > 128 microg/mL, respectively. Sitafloxacin exhibited the most rapid bactericidal activity (> or = log reduction from the initial inoculum) within 2h against all tested strains, including even one levofloxacin-resistant strain. For garenoxacin, bactericidal activity was achieved between 2 and 6 h. Amoxicillin revealed no significant bactericidal activity up to 6 h. Clarithromycin showed no bactericidal activity and did not inhibit growth of a clarithromycin-resistant strain. These data indicate the potential usefulness of sitafloxacin for the treatment of S. pyogenes eradication. PMID:24527519
Namba, Eiko; Okumura, Ryo; Chiba, Megumi; Hoshino, Kazuki; Tateda, Kazuhiro
Plant extracts as natural amoebicidal agents
Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia,\\u000a as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority\\u000a of these infections have been fatal. The aim of our study was to examine the amoebicidal or amoebistatic activity of plant\\u000a extracts
Monika Derda; Edward Hada?; Barbara Thiem
Plant extracts as natural amoebicidal agents.
Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia, as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority of these infections have been fatal. The aim of our study was to examine the amoebicidal or amoebistatic activity of plant extracts from Rubus chamaemorus, Pueraria lobata, Solidago virgaurea and Solidago graminifolia. For the purpose of isolation of pharmacologically active substances, we used the aboveground parts of plants, together with flowers, roots and leaves. It was established that extracts from S. virgauera, P. lobata and R. chamaemorus displayed chemotherapeutic properties in vitro in concentrations of approximately 0.01-0.05 mg extract/mL, i.e., in concentrations of 0.350 microg/mL expressed in ellagic acid for R. chamaemorus and 0.053 microg/mL expressed in puerarin for P. lobata. Therapeutic index values is 3.5-20. As a result of in vivo experiments, it was found out that, following therapy using the extracts, animals infected with Acanthamoeba sp. survived for an extended period (2.5-3 times longer). It was determined that plant extracts may be used both externally and internally in the case of a combined therapy for acanthamoebiasis. The tested extracts are not toxic for animals. PMID:19050923
Derda, Monika; Hada?, Edward; Thiem, Barbara
Plant antimicrobial peptides: an overview of SuperSAGE transcriptional profile and a functional review.
Defensin, thionin and lipid transfer protein (LTP) gene families, which antimicrobial activity has an attractive use in protein engineering and transgenic production of agronomical important plants, have been here functionally reviewed. Also, a transcriptional overview of a set of plant SuperSAGE libraries and analysis looking for 26 bp tags possibly annotated for those families is presented. Tags differentially expressed (p = 0.05) or constitutively transcribed were identified from leaves or roots SuperSAGE libraries from important Brazilian plant species [cowpea (Vigna unguiculata (L.) Walp.), soybean (Glycine max (L.) Merr.) and modern sugarcane hybrids (Saccharum spp.)] submitted to abiotic [salt (100 mM NaCl) or drought] or biotic stresses [fungus inoculation (Phakopsora pachyrhizi; Asiatic Soyben Rust phytopathogen)]. The diverse transcriptional patterns observed, probably related to the variable range of targets and functions involved, could be the first step to unravel the antimicrobial peptide world and the plant stress response relationship. Moreover, SuperSAGE opens the opportunity to find some SNPs or even rare transcript that could be important on plant stress resistance mechanisms. Putative defensin or LTP identified by SuperSAGE following a specific plant treatment or physiological condition could be useful for future use in genetic improvement of plants. PMID:20088771
Kido, E A; Pandolfi, V; Houllou-Kido, L M; Andrade, P P; Marcelino, F C; Nepomuceno, A L; Abdelnoor, R V; Burnquist, W L; Benko-Iseppon, A M
Screening of selected medicinal plants of Nepal for antimicrobial activities
In an ethnopharmacological screening of selected medicinal plants used in Nepal, methanol extracts from 21 plant species were assayed for activity against 8 strains of bacteria and 5 strains of fungi. Duplicate assays were conducted with and without exposure to UV-A radiation to test for light-activated or light-enhanced activity. All 21 of the extracts showed activity against at least 2
R. S. Taylor; N. P. Manandhar; G. H. N. Towers
Effect of mixed antimicrobial agents and flavors in active packaging films.
Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected. PMID:19711918
Gutiérrez, Laura; Escudero, Ana; Batlle, Ramón; Nerín, Cristina
Cytotoxicity, Antimicrobial and Antioxidant Studies of the Different Plant Parts of Mimosa Pudica
The petroleum ether, chloroform and methanol crude extracts of the two different plant parts (aerial part and root) of Mimosa pudica (Mimosaceae) were screened in vitro for cytotoxicity studies by brine shrimp lethality bioassay and antimicrobial screening by disc diffusion method. The methanol crude extract of the aerial part was screened in vitro for antioxidant activity using the 1, 1-diphenyl-2-picrylhydrazyl-hydrate
Sadia Afreen Chowdhury; Jannatul Islam; Mahfujur Rahaman; Rebeka Sultana; Sadia Afreen
In vitro antimicrobial activity of extracts and compounds of some selected medicinal plants from Cameroon
Aim of the studySeven extracts and eight compounds from four selected Cameroonian medicinal plants, Solanecio mannii Hook f. (Asteraceae), Monodora myristica Dunal (Annonaceae), Albizia gummifera (J.F. Gmel) C.A. Smith (Fabaceae\\/Mimosoideae) and Glyphaea brevis (Spreng) Monachino (Tiliaceae), traditionally used for the treatment of hepatitis, parasites and other infectious diseases, were tested in vitro for their antimicrobial activity against Gram-positive (5 species)
Emmanuel Jean Teinkela Mbosso; Silvčre Ngouela; Jules Clément Assob Nguedia; Véronique Penlap Beng; Michel Rohmer; Etienne Tsamo
Molecular characterization and antimicrobial activity of endophytic fungi from coffee plants
Endophytic filamentous fungi from coffee plants (Coffea arabica and C. robusta) deposited in the Brazilian Collection of Environmental and Industrial Microorganisms (CBMAI) were characterized taxonomically by using molecular tools and investigated concerning their antimicrobial activity against different human pathogenic bacteria. Thirty-seven out of 39 CBMAI strains investigated were identified to at least at genus level by ITS and rDNA D1\\/D2
L. D. Sette; M. R. Z. Passarini; C. Delarmelina; F. Salati; M. C. T. Duarte
In Vitro Activities of 15 Antimicrobial Agents against 110 Toxigenic Clostridium difficile Clinical Isolates Collected from 1983 to 2004?
The incidence and severity of Clostridium difficile-associated disease (CDAD) is increasing, and standard treatment is not always effective. Therefore, more-effective antimicrobial agents and treatment strategies are needed. We used the agar dilution method to determine the in vitro susceptibility of the following antimicrobials against 110 toxigenic clinical isolates of C. difficile from 1983 to 2004, primarily from the United States: doripenem, meropenem, gatifloxacin, levofloxacin, moxifloxacin, OPT-80, ramoplanin, rifalazil, rifaximin, nitazoxanide, tizoxanide, tigecycline, vancomycin, tinidazole, and metronidazole. Included among the isolates tested were six strains of the toxinotype III, NAP1/BI/027 group implicated in recent U.S., Canadian, and European outbreaks. The most active agents in vitro were rifaximin, rifalazil, tizoxanide, nitazoxanide, and OPT-80 with MICs at which 50% of the isolates are inhibited (MIC50) and MIC90 values of 0.0075 and 0.015 ?g/ml, 0.0075 and 0.03 ?g/ml, 0.06 and 0.125 ?g/ml, 0.06 and 0.125 ?g/ml, 0.125 and 0.125 ?g/ml, respectively. However, for three isolates the rifalazil and rifaximin MICs were very high (MIC of >256 ?g/ml). Ramoplanin, vancomycin, doripenem, and meropenem were also very active in vitro with narrow MIC50 and MIC90 ranges. None of the isolates were resistant to metronidazole, the only agent for which there are breakpoints, with tinidazole showing nearly identical results. These in vitro susceptibility results are encouraging and support continued evaluation of selected antimicrobials in clinical trials of treatment for CDAD.
Hecht, David W.; Galang, Minerva A.; Sambol, Susan P.; Osmolski, James R.; Johnson, Stuart; Gerding, Dale N.
Detection of tetracycline resistance determinants in pig isolates from three herds with different histories of antimicrobial agent exposure.
A total of 114 gram-negative fecal isolates from domestic pigs in herds with different histories of antimicrobial agent exposure were screened for the presence of plasmid DNA and specific tetracycline resistance determinants. More than 84% of the isolates harbored plasmid DNA, which ranged in size from 2.1 to 186 kb. A total of 78 isolates (68.4%) were resistant to tetracycline at concentrations greater than 4 micrograms/ml. Plasmid DNAs from about 56% of the tetracycline-resistant isolates hybridized with DNA probes for class A, B, C, and D tetracycline resistance determinants. The class B determinant was the most common determinant (35% of the isolates), followed by the class C determinant (12%) and the class A determinant (1%). About 9% of the isolates contained two determinants on plasmids. None of the plasmids from isolates hybridized with the class D determinant probe. The class C determinant was the most prevalent determinant on plasmids in isolates from pigs not exposed to antimicrobial agents for more than 146 months, while the class B determinant was more prevalent on plasmids in isolates from pigs exposed to either subtherapeutic or therapeutic levels of antimicrobial agents. Most tetracycline resistance determinants were localized on plasmids which were more than 30 kb long. A great number of wild-type tetracycline-resistant Escherichia coli strains were found with the class E determinant on their chromosomes. This study revealed a high prevalence of tetracycline resistance determinants in the fecal flora of pig herds whether or not they were fed with antibiotics.
Lee, C; Langlois, B E; Dawson, K A
Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin
In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. Objective This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). Material and Methods Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37şC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37şC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (?=0.05) and the failure modes were visually classified. Results No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. Conclusions Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.
ALCANTARA, Cristiane S.; de MACEDO, Allana F.C.; GURGEL, Bruno C.V.; JORGE, Janaina H.; NEPPELENBROEK, Karin H.; URBAN, Vanessa M.
Effect of Abolishment of the Use of Antimicrobial Agents for Growth Promotion on Occurrence of Antimicrobial Resistance in Fecal Enterococci from Food Animals in Denmark
From 1995 to 2000, a total of 673 Enterococcus faecium and 1,088 Enterococcus faecalis isolates from pigs together with 856 E. faecium isolates from broilers were isolated and tested for susceptibility to four classes of antimicrobial agents used for growth promotion as part of the Danish program of monitoring for antimicrobial resistance. The four antimicrobials were avilamycin, erythromycin, vancomycin, and virginiamycin. Major changes in the use of antimicrobial agents for growth promotion have occurred during the last 6 years in Denmark. The government banned the use of avoparcin in 1995 and of virginiamycin in 1998. Furthermore, the producers have voluntarily stopped all use beginning in 1999. The avoparcin ban in 1995 was followed by a decrease in the occurrence of glycopeptide-resistant E. faecium (GRE) in broilers, from 72.7% in 1995 to 5.8% in 2000. The occurrence of glycopeptide resistance among isolates from pigs remained constant at around 20% from 1995 to 1997. It was shown that, in GRE from pigs, the genes encoding macrolide and glycopeptide resistance were genetically linked and that, following the decrease in the use of tylosin during 1998 and 1999, the occurrence of GRE in pigs decreased to 6.0% in 2000. From 1995 to 1997 the occurrence of erythromycin resistance among E. faecium and E. faecalis isolates from pigs was almost 90%. Use of tylosin decreased considerably during 1998 and 1999, and this decrease was followed by decreases in the occurrence of resistance to 46.7 and 28.1% among E. faecium and E. faecalis isolates from pigs, respectively. Erythromycin resistance among E. faecium isolates from broilers reached a maximum of 76.3% in 1997 but decreased to 12.7% in 2000 concomitantly with more limited use of virginiamycin. Use of virginiamycin increased from 1995 to 1997 and was followed by an increased occurrence of virginiamycin resistance among E. faecium isolates in broilers, from 27.3% in 1995 to 66.2% in 1997. In January 1998 the use of virginiamycin was banned in Denmark, and the occurrence of virginiamycin resistance decreased to 33.9% in 2000. Use of avilamycin increased from 1995 to 1996 and was followed by an increase in avilamycin resistance among E. faecium isolates from broilers, from 63.6% in 1995 to 77.4% in 1996. Since 1996 avilamycin usage has decreased, followed by a decrease in resistance to 4.8% in 2000. Our observations show that it is possible to reduce the occurrence of antimicrobial resistance in a national population of food animals when the selective pressure is removed. Cases in which resistance to vancomycin was linked to resistance to erythromycin were exceptions. In such cases resistance did not decrease until the use of both avoparcin and tylosin was limited.
Aarestrup, Frank M?ller; Seyfarth, Anne Mette; Emborg, Hanne-Dorthe; Pedersen, Karl; Hendriksen, Rene S.; Bager, Flemming
Antimicrobial activity of protoanemonin, a lactone from ranunculaceous plants
Protoanemonin, a component of Ranunculus bulbosus, was tested as an antifungal agent on selected strains of dermatophytes and yeasts. The minimum inhibitory concentrations ranged from 2.0 to 7.5×10-4 M and the minimum lethal concentrations from 3.8×10-4 M to >1.0×10-3 M. The most sensitive dermatophyte tested was Epidermophyton floccosum, and the most sensitive yeast Rhodotorula glutinis. The effects of different culture
Donatella Mares; Corso Porta Mare
Antimicrobial activities of some selected traditional Ethiopian medicinal plants used in the treatment of skin disorders.
Hydroalcoholic extracts of eight species of medicinal plants, namely, Acokanthera schimperi (Apocynaceae), Calpurnia aurea (Leguminosae), Kalanchoe petitiana (Crassulaceae), Lippia adoensis (Verbenaceae), Malva parviflora (Malvaceae), Olinia rochetiana (Oliniaceae), Phytolacca dodecandra (Phytolaccaceae) and Verbascum sinaiticum (Scrophulariaceae), traditionally used in the treatment of various skin disorders were screened for antimicrobial activity against different strains of bacteria and fungi which are known to cause different types of skin infections. The tests were carried out using agar well diffusion method at three concentration levels (100, 50 and 25mg/ml) of the crude extracts. The MICs of the crude extracts of Lippia adoensis and Olinia rochetiana were determined by agar dilution method. Furthermore, the powdered leaves of Lippia adoensis and Olinia rochetiana were fractionated into different solvents of wide ranging polarity and the resulting fractions were screened for antimicrobial activity against the same organisms. Of all the plants tested, Lippia adoensis and Olinia rochetiana were found to be the most active species against bacterial and fungal strains, respectively. In addition, almost all species of plants were found to have activity on at least one microbial strain. The antimicrobial activity profile also showed that Staphylococcus aureus and Trichophyton mentagrophytes were the most susceptible bacterial and fungal strains, respectively. The results indicate the potential of these herbal drugs in treating microbial infections of the skin, thus, justifying their claimed uses in the treatment of various skin disorders, the majority of which are of infectious origin. PMID:16054532
Tadeg, Hailu; Mohammed, Endris; Asres, Kaleab; Gebre-Mariam, Tsige
Cleaning and Sanitizing Agents for Seafood Processing Plants.
National Technical Information Service (NTIS)
Selecting proper cleaning and sanitizing agents is an important first step toward a good sanitation program for your processing plant. Your choice is complicated by the sheer number of products available and by myriad claims of superiority. To make a prop...
J. Lee
Survey of Susceptibilities of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis Isolates to 26 Antimicrobial Agents: a Prospective U.S. Study
An antimicrobial susceptibility surveillance study of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolates was performed during the winter of 1996-1997 in order to determine their susceptibilities to 5 fluoroquinolones and 21 other antimicrobial agents. Broth microdilution MICs were determined for 2,752 isolates from 51 U.S. medical centers. Of the 1,276 S. pneumoniae isolates, 64% were susceptible, 17% were intermediate,
Ixodes scapularis JAK-STAT Pathway Regulates Tick Antimicrobial Peptides, Thereby Controlling the Agent of Human Granulocytic Anaplasmosis
Ixodes scapularis transmits the agent of human granulocytic anaplasmosis, among other pathogens. The mechanisms used by the tick to control Anaplasma phagocytophilum are not known. We demonstrate that the I. scapularis Janus kinase (JAK)–signaling transducer activator of transcription (STAT) pathway plays a critical role in A. phagocytophilum infection of ticks. The A. phagocytophilum burden increases in salivary glands and hemolymph when the JAK-STAT pathway is suppressed by RNA interference. The JAK-STAT pathway exerts its anti-Anaplasma activity presumably through STAT-regulated effectors. A salivary gland gene family encoding 5.3-kDa antimicrobial peptides is highly induced upon A. phagocytophilum infection of tick salivary glands. Gene expression and electrophoretic mobility shift assays showed that the 5.3-kDa antimicrobial peptide–encoding genes are regulated by tick STAT. Silencing of these genes increased A. phagocytophilum infection of tick salivary glands and transmission to mammalian host. These data suggest that the JAK-STAT signaling pathway plays a key role in controlling A. phagocytophilum infection in ticks by regulating the expression of antimicrobial peptides.
Liu, Lei; Dai, Jianfeng; Zhao, Yang O.; Narasimhan, Sukanya; Yang, Ying; Zhang, Lili; Fikrig, Erol
A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one example embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl; and the metallic antimicrobial agent is selected from chelated silver ions, silver metal, chelated copper ions, copper metal, chelated zinc ions, zinc metal and mixtures thereof.
McDonald, William F. (Utica, OH); Wright, Stacy C. (Flint, MI); Taylor, Andrew C. (Ann Arbor, MI)
Therapeutical trials with antimicrobial agents and cultured cecal microflora in Salmonella infantis infections in chickens.
The efficacy of short antimicrobial therapy was examined in chicks infected with S. infantis on the day of hatching. An attempt was made to prevent the reappearance of salmonellae by treating the chicks with a culture of cecal microflora to re-establish the normal intestinal flora. The following drugs were used: neomycin/polymyxin, oxytetracyline/neomycin, dihydrostreptomycin, furazolidone, and trimethoprim/sulphadiazine. The oxytetracycline/neomycin therapy was most effective, but reappearance of the infection was not avoided. Combined therapy with other antimicrobials and the culture reduced the number of infected chicks compared with the respective control groups. A slight reduction was also found when the culture was used alone without any preceding antimicrobial treatment. PMID:523382
Seuna, E; Nurmi, E
Discovery of new anticancer agents from higher plants
1. ABSTRACT Small organic molecules derived from higher plants have been one of the mainstays of cancer chemotherapy for approximately the past half a century. In the present review, selected single chemical entity natural products of plant origin and their semi-synthetic derivatives currently in clinical trials are featured as examples of new cancer chemotherapeutic drug candidates. Several more recently isolated compounds obtained from plants showing promising in vivo biological activity are also discussed in terms of their potential as anticancer agents, with many of these obtained from species that grow in tropical regions. Since extracts of only a relatively small proportion of the ca. 300,000 higher plants on earth have been screened biologically to date, bioactive compounds from plants should play an important role in future anticancer drug discovery efforts.
Pan, Li; Chai, Hee-Byung; Kinghorn, A. Douglas
Salicylanilide esters of N-protected amino acids as novel antimicrobial agents.
A series of novel, highly antimicrobial salicylanilide esters of N-protected amino acids were synthesized and characterized. Their in vitro antimicrobial activity against eight fungal strains and Mycobacterium tuberculosis was determined. The compounds had the highest level of activity against Aspergillus fumigatus, Absidia corymbifera and Trichophyton mentagrophytes, and these levels were higher than that of the standard drug fluconazole. In addition, three compounds showed interesting antituberculosis activity, with inhibition ranging from 89% to 99%. (S)-4-Chloro-2-(4-trifluoromethylphenylcarbamoyl)-phenyl 2-benzyloxy-carbonylamino-propionate had the highest level of both antifungal and antimycobacterial activity. The structure-activity relationships of the new compounds are discussed. PMID:19081718
Imramovský, Ales; Vinsová, Jarmila; Férriz, Juana Monreal; Buchta, Vladimír; Jampílek, Josef
Cefotetan: a second-generation cephalosporin active against anaerobic bacteria. Committee on Antimicrobial Agents, Canadian Infectious Disease Society.
OBJECTIVE: To offer guidelines for the use of cefotetan, a cephamycin antibiotic, in order to minimize its overprescription. OPTIONS: Clinical practice options considered were treatment of infections with the use of second- and third-generation cephalosporins, carbapenems such as imipenem as well as combination regimens of agents active against anaerobic bacteria, such as metronidazole or clindamycin with an aminoglycoside. OUTCOMES: In order of importance: efficacy, side effects and cost. EVIDENCE: A MEDLINE search of articles published between January 1982 and December 1993. In-vitro and pharmacokinetic studies published in recognized peer-reviewed journals that used recognized standard methods with appropriate controls were reviewed. For results of clinical trials, the reviewers emphasized randomized double-blind trials with appropriate controls. VALUES: The Antimicrobial Agents Committee of the Canadian Infectious Disease Society (CIDS) and a recognized expert (M.J.G.) recommended use of cefotetan to prevent and treat infections against which it has proved effective in randomized controlled trials. BENEFITS, HARMS AND COSTS: These guidelines should lead to less inappropriate prescribing of cefotetan, with its attendant costs and risk of development of resistant bacteria. RECOMMENDATIONS: Cefotetan could be considered an alternative single agent for prophylaxis of infection in patients undergoing elective bowel surgery. It may be used to treat patients with acute pelvic inflammatory disease and endometritis. VALIDATION: This article was prepared, reviewed and revised by the Committee on Antimicrobial Agents of the CIDS. It was then reviewed by the Council of the CIDS, and any further necessary revisions were made by the chairman of the committee.
Gribble, M J
Antimicrobial terpenoids from the oleoresin of the Peruvian medicinal plant Copaifera paupera.
Twelve known diterpenes 1 - 11 and 13, and three known sesquiterpenes 14 - 16, along with a new C(20) - C(15) terpenoid 17, with a structure based on an unprecedented skeleton in which a labdane diterpene is linked to a monocyclic sesquiterpene by an ester bridge, were isolated from the oleoresin of the Peruvian medicinal plant Copaifera paupera (Herzog) Dwyer (Leguminosae). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC), and by comparison with data in the literature. The leishmanicidal, antimicrobial, cytotoxic, and aldose reductase inhibitory activities were studied. Compounds 1 and 11 showed significant antimicrobial activity (MIC < 10 microg/ml) against Gram-positive bacteria, comparable with cephotaxime used as control. Compound 2 exhibited moderate cytotoxic activity against four cancer cell lines. PMID:12357392
Tincusi, Benigna M; Jiménez, Ignacio A; Bazzocchi, Isabel L; Moujir, Laila M; Mamani, Zulma A; Barroso, José P; Ravelo, Angel G; Hernández, Basilio V
Biodiversity of thermotolerant Bacillus sp. producing biosurfactants, biocatalysts, and antimicrobial agents
Thermotolerant bacteria isolated from soil and water samples taken from 76 hot springs in Thailand were investigated for their biosurfactant, biocatalytic, and antimicrobial properties. DNA samples purified from 148 pure isolates were PCR amplified using primers specific for the 16S rDNA hypervariable region of the genus Bacillus. The DNAPAR phylogenetic tree clearly demonstrated that these isolates were related to Bacillus
Arda Pakpitcharoena
Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants.
Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC-MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50?g). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic-water extracts were 1119 and 1966mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity. PMID:23017418
Jaberian, Hamideh; Piri, Khosro; Nazari, Javad
[Use of antimicrobial agents and prevalence of infection at the Clinical University Hospital of Zaragoza].
Two cross-sectional prevalence studies have been performed on april 10 and June 12, 1986, at the Hospital Clínico Universitario of Zaragoza in order to gather information about the use and consumption of antimicrobial drugs and the degree of hospital infection. On these days, of the 726 and 717 patients admitted to the hospital, 29.3% and 26.3% were treated with antimicrobial drugs and, of these, 31.4% and 23.8% respectively, with associate drugs (above all empirical purposes and for respiratory infections), aminoglycosides being the most common. The indication of antimicrobial drugs was distributed in the following manner on both days: prophylactic 28.7% and 25.1%, empirical 42.3% and 56.9% and therapeutical 27.9% and 17.6%. The prophylactic treatments were correct in 46.1% and 36.6% of the cases, and of those 74.3% and 71.6% were for surgical prophylaxis; the average time was 3.5 and 4.5 days on each day studied. The most commonly used antimicrobial drugs were, in decreased order: gentamicin, amoxycilin, ampicillin, cefoxitin, pipemidic acid and cefamandol. The consumption was 1.36 and 1.29 drugs per patient on each day. The most common routes of administration were I.V. and oral. The intervals and dosages were generally respected. The most frequent were respiratory and urinary infections, and of these, 21% and 32% of the respiratory infections were nosocomial as were 23% and 32% of the urinary infection. 7.1% and 4.3% of the patients admitted developed a hospital-acquired infection on each day. The most frequent isolated germs were Escherichia coli and Pseudomonas aeruginosa. There were no adverse reactions to the antimicrobial drugs documented. PMID:2709905
Mateo Arrizabalaga, M; Bartolomé Rodríguez, M; Faure Nogueras, E; Hortells Aznar, J L
Comparison of MICs of Ceftiofur and Other Antimicrobial Agents against Bacterial Pathogens of Swine from the United States, Canada, and Denmark
The MICs of ceftiofur and other antimicrobial agents, tested for comparison, for 515 bacterial isolates of pigsfromtheUnitedStates,Canada,andDenmarkwithvariousdiseaseswerecompared.Theorganismstested includedActinobacillus pleuropneumoniae,Escherichia coli,Pasteurella multocida,Salmonella choleraesuis,Salmo- nella typhimurium,Streptococcus suis,Streptococcus dysgalactiaesubsp.equisimilis,Streptococcus equisubsp.equi, and Streptococcus equi subsp. zooepidemicus. In addition to ceftiofur, the following antimicrobial agents or combinations were tested: enrofloxacin, ampicillin, sulfamethazine, trimethoprim-sulfadiazine (1:19), eryth- romycin, lincomycin, spectinomycin, lincomycin-spectinomycin (1:8), tilmicosin, and tetracycline. Tilmicosin was
Cyclodextrins as encapsulation agents for plant bioactive compounds.
Plants possess a wide range of molecules capable of improve healing: fibre, vitamins, phytosterols, and further sulphur-containing compounds, carotenoids, organic acid anions and polyphenolics. However, they require an adequate level of protection from the environmental conditions to prevent losing their structural integrity and bioactivity. Cyclodextrins are cyclic oligosaccharides arising from the degradation of starch, which can be a viable option as encapsulation technique. Cyclodextrins are inexpensive, friendly to humans, and also capable of improving the biological, chemical and physical properties of bioactive molecules. Therefore, the aim of this review is to highlight the use of cyclodextrins as encapsulating agents for bioactive plant molecules in the pharmaceutical field. PMID:24299757
Pinho, Eva; Grootveld, Martin; Soares, Graça; Henriques, Mariana
Adaptive Resistance to Biocides in Salmonella enterica and Escherichia coli O157 and Cross-Resistance to Antimicrobial Agents
The mechanisms by which bacteria resist killing by antibiotics and biocides are still poorly defined, although repeated exposure to sublethal concentrations of antibacterial agents undoubtedly contributes to their development. This study aimed both to investigate the potential of Salmonella enterica and Escherichia coli O157 for adaptive resistance to commonly used biocides and to determine any cross-resistance to antibiotics. Strains were repeatedly passaged in media containing increasing concentrations of a biocide or antibiotic until adaptive resistance was obtained. A wide panel of antimicrobial agents was then screened by using the adapted strain to determine cross-resistance, if any. Adaptive resistance was readily achieved for both S. enterica and E. coli O157. Cross-resistance in adaptively resistant S. enterica varied with the serotype; Salmonella enterica serovar Enteritidis expressed cross-resistance to chloramphenicol, whereas Salmonella enterica serovar Typhimurium expressed cross-resistance to chlorhexidine. Benzalkonium chloride-resistant Salmonella enterica serovar Virchow showed elevated resistance to chlorhexidine; however, chlorhexidine-resistant Salmonella serovar Virchow did not demonstrate reciprocal cross-resistance to benzalkonium chloride, suggesting specific rather than generic resistance mechanisms. E. coli O157 strains acquired high levels of resistance to triclosan after only two sublethal exposures and, when adapted, repeatedly demonstrated decreased susceptibilities to various antimicrobial agents, including chloramphenicol, erythromycin, imipenem, tetracycline, and trimethoprim, as well as to a number of biocides. These observations raise concern over the indiscriminate and often inappropriate use of biocides, especially triclosan, in situations where they are unnecessary, whereby they may contribute to the development of microbial resistance mechanisms.
Braoudaki, M.; Hilton, A. C.
Synthesis, molecular modeling and structural characterization of vanillin derivatives as antimicrobial agents
NASA Astrophysics Data System (ADS)
Two vanillin derivatives have been designed and synthesized and their biological activities were also evaluated for antimicrobial activity. Their chemical structures are characterized by single crystal X-ray diffraction studies, 1H NMR, MS, and elemental analysis. Structural stabilization of them followed by intramolecular as well as intermolecular H-bonds makes these molecules as perfect examples in molecular recognition with self-complementary donor and acceptor units within a single molecule. Docking simulations have been performed to position compounds into the FtsZ active site to determine their probable binding model. Compound 3a shows the most potent biological activity, which may be a promising antimicrobial leading compound for the further research.
Sun, Juan; Yin, Yong; Sheng, Gui-Hua; Yang, Zhi-Bo; Zhu, Hai-Liang
Optimization and production of pyrrolidone antimicrobial agent from marine sponge-associated Streptomyces sp. MAPS15.
Twenty-nine actinobacterial strains were isolated from marine sponge Spongia officinalis and screened for antagonistic activity against various bacterial and fungal pathogens. The active antibiotic producer MAPS15 was identified as Streptomyces sp. using 16S rRNA phylogenetic analysis. The critical control factors were selected from Plackett-Burman (PB) factorial design and the bioprocess medium was optimized by central composite design (CCD) for the production of bioactive metabolite from Streptomyces sp. MAPS15. The maximum biomass and active compound production obtained with optimized medium was 6.13 g/L and 62.41 mg/L, respectively. The economical carbon source, paddy straw was applied for the enhanced production of bioactive compound. The purified active fraction was characterized and predicted as pyrrolidone derivative which showed broad spectrum of bioactivity towards indicator organisms. The predicted antimicrobial spectra suggested that the Streptomyces sp. MAPS15 can produce a suite of novel antimicrobial drugs. PMID:23917410
Sathiyanarayanan, G; Gandhimathi, R; Sabarathnam, B; Seghal Kiran, G; Selvin, Joseph
A novel antimicrobial protein for plant protection consisting of a Xanthomonas oryzae harpin and active domains of cecropin A and melittin
Summary Discoveries about antimicrobial peptides and plant defence activators have made possible the de novo and rational design of novel peptides for use in crop protection. Here we report a novel chimeric protein, Hcm1, which was made by linking the active domains of cecropin A and melittin to the hypersensitive response (HR)?elicitor Hpa1 of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak. The resulting chimeric protein maintained not only the HR?inducing property of the harpin, but also the antimicrobial activity of the cecropin A?melittin hybrid. Hcm1 was purified from engineered Escherichia coli and evaluated in terms of the minimal inhibitory concentration (MIC) and the 50% effective dose (ED50) against important plant pathogenic bacteria and fungi. Importantly, the protein acted as a potential pesticide by inducing disease resistance for viral, bacterial and fungal pathogens. This designed drug can be considered as a lead compound for use in plant protection, either for the development of new broad?spectrum pesticides or for expression in transgenic plants.
Che, Yi-Zhou; Li, Yu-Rong; Zou, Hua-Song; Zou, Li-Fang; Zhang, Bing; Chen, Gong-You
Studies of the in vitro anticancer, antimicrobial and antioxidant potentials of selected Yemeni medicinal plants from the island Soqotra
BACKGROUND: Recent years have witnessed that there is a revival of interest in drug discovery from medicinal plants for the maintenance of health in all parts of the world. The aim of this work was to investigate 26 plants belonging to 17 families collected from a unique place in Yemen (Soqotra Island) for their in vitro anticancer, antimicrobial and antioxidant
Ramzi A Mothana; Ulrike Lindequist; Renate Gruenert; Patrick J Bednarski
Use of mandelic acid condensation polymer (SAMMA), a new antimicrobial contraceptive agent, for vaginal prophylaxis
Objective: To assess the contraceptive properties, antimicrobial activity, and safety of mandelic acid condensation polymer (SAMMA).Design: Experimental study of SAMMA's in vitro and in vivo properties.Setting: Academic research laboratories.Patient(s): Healthy volunteers for semen donation in an academic research environment.Intervention(s): Inhibition of sperm function indicators, conception, sexually transmitted infection-causing pathogens (including HIV), and lactobacilli was evaluated. Safety indicators were studied.Main Outcome
Lourens J. D Zaneveld; Robert A Anderson; Xiao-Hui Diao; Donald P Waller; Calvin Chany; Kenneth Feathergill; Gustavo Doncel; Morris D Cooper; Betsy Herold
Ethiopian traditional herbal drugs. Part II: Antimicrobial activity of 63 medicinal plants.
A total of 315 extracts/fractions from 63 traditionally used Ethiopian plants were subjected to antimicrobial screening using known strains of Staphylococcus aureus, Salmonella gallinarum, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans. The agar plate well-diffusion method was used at a sample concentration of 1000 micrograms/ml; it was found that all of the plants showed activity against one or more of the microorganism(s). Direct aqueous extracts from six plants were found to be active against all of the test organisms. These findings confirm traditional therapeutic claims for aqueous dosage forms of these herbs. The relative susceptibility of the test organisms to the five types of extracts/fractions indicated a decreasing rank order of: S. aureus, P. aeruginosa, C. albicans, S. gallinarum, E. coli, K. pneumoniae and P. vulgaris. PMID:8412246
Desta, B
Which Approach Is More Effective in the Selection of Plants with Antimicrobial Activity?
The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000?µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities.
Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lucia Cavalcanti; Albuquerque, Ulysses Paulino
Which approach is more effective in the selection of plants with antimicrobial activity?
The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000?µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities. PMID:23878595
Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lúcia Cavalcanti; Albuquerque, Ulysses Paulino
Preliminary Screening of Endophytic Fungi from Medicinal Plants in Malaysia for Antimicrobial and Antitumor Activity
The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay.
Radu, Son; Kqueen, Cheah Yoke
Metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.
The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides), and balsam poplar (P. balsamifera) among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees. PMID:24204850
Wilson, Michael B; Spivak, Marla; Hegeman, Adrian D; Rendahl, Aaron; Cohen, Jerry D
Molecular characterization of Pseudomonas aeruginosa isolates resistant to all antimicrobial agents, but susceptible to colistin, in Daegu, Korea.
Multi-drug resistant Pseudomonas aeruginosa has been implicated in a variety of serious therapeutic problems in clinical environments. Among the 968 P. aeruginosa isolates obtained from two hospitals in Daegu, Korea, we acquired 17 isolates that were resistant to all available tested antimicrobial agents, with the exception of colistin (colistin-only sensitive). We characterized the antimicrobial susceptibilities, metallo-beta-lactamases, and epidemiological relatedness among the colistin-only sensitive P. aeruginosa isolates. All colistin-only sensitive isolates were positive in the modified Hodge test and imipenem-EDTA synergy test, thereby indicating the production of metallo-beta-lactamases. 11 isolates from the secondary hospital and six isolates from the tertiary teaching hospital harbored blaVIM-2 and blaIMP-1, respectively. The pulsed-field gel electrophoretic analysis of the SpeI-digested DNA from P. aeruginosa isolates indicated that two different clones of colistin-only sensitive P. aeruginosa originated from each hospital, and had spread within the hospital environment. Overall, colistin-only sensitive P. aeruginosa was detected in Korea for the first time, but no pan-drug resistant bacteria were identified. Nationwide surveillance is required in order to monitor the emergence of colistin-only sensitive or pan-drug resistant bacteria. PMID:17846591
Lee, Yoo Chul; Ahn, Byung Jun; Jin, Jong Sook; Kim, Jung Uk; Lee, Sang Hwa; Song, Do Young; Lee, Won Kil; Lee, Je Chul
[Antimicrobial activities of ant Ponericin W1 against plant pathogens in vitro and the disease resistance in its transgenic Arabidopsis].
The antimicrobial peptides (AMPs) exhibit a broad antimicrobial spectrum. The application of AMPs from non-plant organisms attracts considerable attention in plant disease resistance engineering. Ponericin W1, isolated from the venom of ant (Pachycondyla goeldii), shows antimicrobial activities against Gram-positive bacteria, Gram-negative bacteria and the budding yeast (Saccharomyces cerevisiae); however, it is not clear whether Ponericin W1 is effective against plant pathogens. The results of this study indicated synthesized Ponericin W1 inhibited mycelial growth of Magnaporthe oryzae and Botrytis cinerea, as well as hyphal growth and spore production of Fusarium graminearum. Besides, Ponericin W1 exhibited antibacterial activities against Pseudomonas syringae pv. tomato and Xanthomonas oryzae pv. oryzae. After codon optimization, Ponericin W1 gene was constructed into plant expression vector, and transformed into Arabidopsis thaliana by floral dip method. The Ponericin W1 was located in intercellular space of the transgenic plants as expected. Compared with the wild-type plants, there were ungerminated spores and less hyphal, conidia on the leaves of transgenic plants after innoculation with the powdery mildew fungus Golovinomyces cichoracearum. After innoculation with the pathogenic bac-terium Pseudomonas syringae pv. tomato, the baceria in the leaves of transgenic plants was significantly less than the wild-type plants, indicating that the transgenic plants displayed enhanced disease resistance to pathogens. These results demonstrate a potential use of Ponericin W1 in genetic engineering for broad-spectrum plant disease resistance. PMID:23956091
Chen, Yong-Fang; Sun, Peng-Wei; Tang, Ding-Zhong
Food Antimicrobials Nanocarriers
Natural food antimicrobials are bioactive compounds that inhibit the growth of microorganisms involved in food spoilage or food-borne illness. However, stability issues result in degradation and loss of antimicrobial activity. Nanoencapsulation allows protection of antimicrobial food agents from unfavorable environmental conditions and incompatibilities. Encapsulation of food antimicrobials control delivery increasing the concentration of the antimicrobials in specific areas and the improvement of passive cellular absorption mechanisms resulted in higher antimicrobial activity. This paper reviews the present state of the art of the nanostructures used as food antimicrobial carriers including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers.
Blanco-Padilla, Adriana; Soto, Karen M.; Hernandez Iturriaga, Montserrat
New quaternary ammonium polymers as antimicrobial agents. Part II. Alkylation products of linear aliphatic poly (aminodisulphides)
Two new polymeric disulphides containing t-amino groups in their main chain, namely poly[1,8-(3,6-dimethyl-3,6-diaza) octaine diyl disulphide] (5) and poly[1,8-(1,12-(3,10-dimethyl-3,10-diaza) dodecane diyl disulphide] (6) were prepared by the polyoxidation of 3,6-dimethyl-3,6-diazaoctane-1,8-dithiol (3) and 3,10-dimethyl-3,10-diazadodecane-1,12-dithiol (4), respectively. They were quaternized with methyl iodide and benzyl bromide, and the resulting quaternary ammonium polymers were preliminarily tested for antimicrobial activity against Escherichia coli K12,
Elisabetta Ranucci; Paolo Ferruti; Maria Grazia Neri
In Vitro Antimicrobial Activity of Extracts from Plants Used Traditionally in South Africa to Treat Tuberculosis and Related Symptoms
Respiratory ailments are major human killers, especially in developing countries. Tuberculosis (TB) is an infectious disease causing a threat to human healthcare. Many South African plants are used in the traditional treatment of TB and related symptoms, but there has not been a sufficient focus on evaluating their antimicrobial properties. The aim of this study was to evaluate the antimicrobial properties of plants used traditionally to treat TB and related symptoms against microorganisms (Klebsiella pneumoniae, Staphylococcus aureus, and Mycobacterium aurum A+) associated with respiratory infections using the microdilution assay. Ten plants were selected based on a survey of available literature of medicinal plants used in South Africa for the treatment of TB and related symptoms. The petroleum ether, dichloromethane, 80% ethanol, and water extracts of the selected plants were evaluated for antibacterial activity. Out of 68 extracts tested from different parts of the 10 plant species, 17 showed good antimicrobial activities against at least one or more of the microbial strains tested, with minimum inhibitory concentration ranging from 0.195 to 12.5?mg/mL. The good antimicrobial properties of Abrus precatorius, Terminalia phanerophlebia, Indigofera arrecta, and Pentanisia prunelloides authenticate their traditional use in the treatment of respiratory diseases. Thus, further pharmacological and phytochemical analysis is required.
Madikizela, Balungile; Ndhlala, Ashwell Rungano; Finnie, Jeffrey Franklin; Staden, Johannes Van
Susceptibility trends of haemophilus influenzae and Moraxella catarrhalis against orally administered antimicrobial agents: five-year report from the SENTRY Antimicrobial Surveillance Program
The assessment of orally administered antimicrobial susceptibilities of common pathogens that cause community-acquired respiratory tract infections (CARTI) has become exceedingly important due to the number of office visits for this indication. Numerous local, regional and global studies have documented the susceptibilities of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis, the most common CARTI pathogens. SENTRY Antimicrobial Surveillance Program sites in
D. M Johnson; H. S Sader; T. R Fritsche; D. J Biedenbach; Ronald N Jones
Acute, Multiple-Dose Dermal and Genetic Toxicity of Nu-3: A Novel Antimicrobial Agent
Nu-3 [butyl-phosphate-5?-thymidine-3?-phosphate-butyl] is a modified nucleotide that has been shown to have antimicrobial activity against a range of bacteria including Pseudomonas aeruginosa. However, data on the toxicological profile of Nu-3 are still lacking. In the present study, the toxicity of Nu-3 was evaluated by the following studies: acute oral toxicity, dermal and mucous membrane irritation, multiple-dose toxicity and genotoxicity in vivo and vitro. The acute oral toxicity test in mice showed that Nu-3 had an LD50 of 2001mg/kg body weight. The irritation tests on rats revealed that Nu-3 was not irritant, with an irritation scoring of 0. The multiple-dose toxicity study in rats showed that Nu-3 did not cause significant changes in histology, selected serum chemistry, and hematological parameters compared to the controls. Rats administrated with multiple-doses of Nu-3 showed no visible toxic symptoms. Both in vitro and in vivo, Nu-3 exhibited no notable genetic toxicity. Overall, the data suggest that Nu-3 is hypotoxic or nontoxic antimicrobial compound that warrants being further developed for treating Pseudomonas aeruginosa infection.
Sun, Juan; Hu, Yanxin; Cao, Shanping; Zhang, Guozhong; Sun, Lun-Quan; Wang, Ming
Biodegradable gelatin-chitosan films incorporated with essential oils as antimicrobial agents for fish preservation.
Essential oils of clove (Syzygium aromaticum L.), fennel (Foeniculum vulgare Miller), cypress (Cupressus sempervirens L.), lavender (Lavandula angustifolia), thyme (Thymus vulgaris L.), herb-of-the-cross (Verbena officinalis L.), pine (Pinus sylvestris) and rosemary (Rosmarinus officinalis) were tested for their antimicrobial activity on 18 genera of bacteria, which included some important food pathogen and spoilage bacteria. Clove essential oil showed the highest inhibitory effect, followed by rosemary and lavender. In an attempt to evaluate the usefulness of these essential oils as food preservatives, they were also tested on an extract made of fish, where clove and thyme essential oils were the most effective. Then, gelatin-chitosan-based edible films incorporated with clove essential oil were elaborated and their antimicrobial activity tested against six selected microorganisms: Pseudomonas fluorescens, Shewanella putrefaciens, Photobacterium phosphoreum, Listeria innocua, Escherichia coli and Lactobacillus acidophilus. The clove-containing films inhibited all these microorganisms irrespectively of the film matrix or type of microorganism. In a further experiment, when the complex gelatin-chitosan film incorporating clove essential oil was applied to fish during chilled storage, the growth of microorganisms was drastically reduced in gram-negative bacteria, especially enterobacteria, while lactic acid bacteria remained practically constant for much of the storage period. The effect on the microorganisms during this period was in accordance with biochemical indexes of quality, indicating the viability of these films for fish preservation. PMID:20688230
Gómez-Estaca, J; López de Lacey, A; López-Caballero, M E; Gómez-Guillén, M C; Montero, P
Frequency of Resistance in Obligate Anaerobic Bacteria Isolated from Dogs, Cats, and Horses to Antimicrobial Agents
Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ? 16/8 ?g/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ? 2 ?g/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ? 32 ?g/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ? 8 ?g/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ? 32 ?g/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ? 2 ?g/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro.
Taylor, A.; Fajt, V. R.
Photodynamic therapy based on 5-aminolevulinic acid and its use as an antimicrobial agent.
Exogenous 5-aminolevulinic acid (ALA) is taken up directly by bacteria, yeasts, fungi, and some parasites, which then induces the accumulation of protoporphyrin IX (PPIX). Subsequent light irradiation of PPIX leads to the inactivation of these organisms via photodamage to their cellular structures. ALA uptake and light irradiation of PPIX produced by host cells leads to the inactivation of other parasites, along with some viruses, via the induction of an immune response. ALA-mediated PPIX production by host cells and light irradiation result in the inactivation of other viruses via either the induction of a host cell response or direct photodynamic attack on viral particles. This ALA-mediated production of light-activated PPIX has been extensively used as a form of photodynamic therapy (PDT) and has shown varying levels of efficacy in treating conditions that are associated with microbial infection, ranging from acne and verrucae to leishmaniasis and onychomycosis. However, for the treatment of some of these conditions by ALA-based PDT, the role of an antimicrobial effect has been disputed and in general, the mechanisms by which the technique inactivates microbes are not well understood. In this study, we review current understanding of the antimicrobial mechanisms used by ALA-based PDT and its role in the treatment of microbial infections along with its potential medical and nonmedical applications. PMID:21793017
Harris, Frederick; Pierpoint, Lynne
Stenusine, an antimicrobial agent in the rove beetle genus Stenus (Coleoptera, Staphylinidae)
NASA Astrophysics Data System (ADS)
Stenusine is well known as the alkaloid, discharged by the rove beetle, genus Stenus Latreille (Coleoptera, Staphylinidae). The Stenus beetles employ the alkaloid as an escape mechanism when on water surfaces. In the case of danger, they lower their abdomen and emit stenusine from their pygidial glands. Stenusine shows a low surface tension and therefore a high spreading pressure; these properties propel the beetle quickly over the water. Many Steninae do not live in habitats with open waters, but in detritus, leaf litter, mosses, etc. This raises the possibility that stenusine might also have another function, e.g., as antibiotic or fungicide. Stenus beetles show an intense grooming behaviour. With gas chromatography mass spectrometry analyses we could prove that they cover themselves with their secretion. To tests its antimicrobial properties we conducted agar diffusion tests with stenusine and norstenusine, another substance that is abundant in most Stenus species. Both compounds have an antimicrobial effect on entomopathogenic bacteria and fungi. Stenusine not only allows for an extraordinary method of locomotion on water surfaces, it also protects the Steninae from being infested with microorganisms.
Lusebrink, Inka; Dettner, Konrad; Seifert, Karlheinz
Spiroplasmas: infectious agents of plants, arthropods and vertebrates.
The spiroplasmas are mollicutes characterized by motility and helical morphology. They were discovered through studies on corn stunt and citrus stubborn diseases. The stubborn agent was the first mollicute of plant origin to be obtained in culture and the first cultured mollicute to possess a helical morphology. The citrus pathogen has been known as Spiroplasma citri since 1973. The corn stunt agent was cultured in 1975 and fully characterized as Spiroplasma kunkelii by 1986. The third and only other phytopathogenic spiroplasma is Spiroplasma phoeniceum, cultured from naturally infected periwinkle plants in Syria and described in 1986. These three spiroplasmas are restricted to the phloem sievetubes of the infected plants and are transmitted from plant by various phloem feeding leafhopper vectors in which the spiroplasmas multiply. Following the pioneering work on S. citri and S. kunkelii, close to fifty other spiroplasma species or proposed species have been discovered. All spiroplasmas have been isolated from insects, ticks and plants. Insects are particularly rich sources of spiroplasmas. Some insect-derived spiroplasmas are entomopathogens. S. melliferum and S. apis are honey bee pathogens. They cross the insect-gut barrier and reach the hemolymph, where they multiply abundantly and kill the bee. Spiroplasma floricola is the agent of lethargy disease of Melolontha melolontha (cockchafer). Spiroplasma poulsonii infects the neotropical species of Drosophila, is transmitted transovarially and kills the male progeny of an infected female fly, hence the name sex ratio spiroplasma. Some insect-derived spiroplasmas are also found on plant (flower) surfaces. For instance, S. apis was cultured from the surfaces of flowers growing in the vicinity of affected beehives. This suggests that the plant surface spiroplasmas are deposited on these surfaces by contaminated insects. Many insect spiroplasmas are not pathogenic, are often restricted to the gut and may be regarded as mutualists or incidental commensals. Of the three known tick spiroplasmas, only Spiroplasma mirum obtained from rabbit ticks is pathogenic to the vertebrate animal (chick embryo, new-born rodents, adult rabbit), but only upon experimental inoculation of the spiroplasma. Strain SMCA induces high incidence of cataracts in new born rodents. With strain GT-48 no cataracts are observed, but fatal encephalitis occurs. Spiral membranous inclusions resembling spiroplasmas have been seen in brain biopsies taken from patients with Creutzfeldt-Jakob disease. However, failure to detect spiroplasmas by serology and culture points to the absence of spiroplasmal involvement in spongiform encephalopathies. Transposon Tn 4001 mutagenesis has been applied for the first time to Spiroplasma citri, and pathogenicity can now be studied at the genetic level. One Tn 4001 mutant does not multiply in the leafhoppers and is, therefore, not transmitted to the plant. Another mutant multiplies well in the plant and is transmitted to the plant, where it reaches high titers, but without inducing symptoms in the plant. In this non-phytopathogenic mutant, Tn 4001 is inserted in the spiroplasmal fructose operon, and the mutant is unable to use fructose. Finally, to study involvement of spiroplasmal motility in pathogenicity, a non-motile mutant has been obtained. Motility was restored by complementation with the wild type genes. This is the first time that successful complementation has been reported, not only in the spiroplasmas but in the mollicutes in general. Undoubtedly, studies on pathogenicity have entered a new era. PMID:9286068
Bové, J M
Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.
Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork. PMID:23834804
Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel
Evaluation of the Antimicrobial Activities of Plant Oxylipins Supports Their Involvement in Defense against Pathogens1[W
Plant oxylipins are a large family of metabolites derived from polyunsaturated fatty acids. The characterization of mutants or transgenic plants affected in the biosynthesis or perception of oxylipins has recently emphasized the role of the so-called oxylipin pathway in plant defense against pests and pathogens. In this context, presumed functions of oxylipins include direct antimicrobial effect, stimulation of plant defense gene expression, and regulation of plant cell death. However, the precise contribution of individual oxylipins to plant defense remains essentially unknown. To get a better insight into the biological activities of oxylipins, in vitro growth inhibition assays were used to investigate the direct antimicrobial activities of 43 natural oxylipins against a set of 13 plant pathogenic microorganisms including bacteria, oomycetes, and fungi. This study showed unequivocally that most oxylipins are able to impair growth of some plant microbial pathogens, with only two out of 43 oxylipins being completely inactive against all the tested organisms, and 26 oxylipins showing inhibitory activity toward at least three different microbes. Six oxylipins strongly inhibited mycelial growth and spore germination of eukaryotic microbes, including compounds that had not previously been ascribed an antimicrobial activity, such as 13-keto-9(Z),11(E),15(Z)-octadecatrienoic acid and 12-oxo-10,15(Z)-phytodienoic acid. Interestingly, this first large-scale comparative assessment of the antimicrobial effects of oxylipins reveals that regulators of plant defense responses are also the most active oxylipins against eukaryotic microorganisms, suggesting that such oxylipins might contribute to plant defense through their effects both on the plant and on pathogens, possibly through related mechanisms.
Prost, Isabelle; Dhondt, Sandrine; Rothe, Grit; Vicente, Jorge; Rodriguez, Maria Jose; Kift, Neil; Carbonne, Francis; Griffiths, Gareth; Esquerre-Tugaye, Marie-Therese; Rosahl, Sabine; Castresana, Carmen; Hamberg, Mats; Fournier, Joelle
The cytotoxic effects of commonly used topical antimicrobial agents on human fibroblasts and keratinocytes.
This study evaluated the cytotoxicity of commonly used topical agents to human dermal fibroblasts and epidermal keratinocytes, which play a prominent role in wound healing. The effects of these topical agents were assessed using two separate assays for the fibroblasts--tritiated thymidine incorporation and the uptake of a vital dye (neutral red). Keratinocytes were evaluated with the neutral red assay. Serial dilutions of each of 10 commonly used topical agents produced decreases in both the uptake of neutral red and the incorporation of thymidine at clinically relevant doses. Only Neosporin G.U. irrigant showed no significant difference compared with controls in the assays for both the fibroblasts and the keratinocytes. Careful attention must be paid to which agent is used in the clinical setting, since many of these can have profound effects on cells that influence wound healing. PMID:2056541
Cooper, M L; Laxer, J A; Hansbrough, J F
In Vitro Activities of 15 Antimicrobial Agents against Clinical Isolates of South African Enterococci
The activities of a panel of currently available antibiotics and the investigational agents LY 333328, linezolid, CL 331,002, CL 329,998, moxifloxacin (BAY 12-8039), trovafloxacin, and quinupristin-dalfopristin against 274 clinical isolates of enterococci were determined. No vancomycin resistance or ?-lactamase production was observed. Except for 12 isolates (all non-Enterococcus faecalis) showing reduced susceptibility to quinupristin-dalfopristin (MIC, ?4 ?g/ml), the new agents exhibited promising in vitro antienterococcal activity.
Struwig, M. C.; Botha, P. L.; Chalkley, L. J.
Development of new benzo[b]thiophene amide-based antimicrobial agents
The overall aim of this project was to investigate the synthesis and activity of a range of compounds based on the benzo[b]thiophene-2-carboxamide structural motif as potential new antimalarial agents, and to a lesser extent as antibacterial agents.\\u000aIn order to subsequently explore any structure-biological activity relationships, the first part of the project involved the systematic synthesis of some 39 non-fused
Johana M Mbere
Structure, antimicrobial activity, DNA- and albumin-binding of manganese(II) complexes with the quinolone antimicrobial agents oxolinic acid and enrofloxacin.
The reaction of MnCl2 with the quinolone antibacterial drug oxolinic acid (Hoxo) results to the formation of [KMn(oxo)3(MeOH)3]. Interaction of MnCl2 with the quinolone Hoxo or enrofloxacin (Herx) and the N,N'-donor heterocyclic ligand 1,10-phenanthroline (phen) results in the formation of metal complexes with the general formula [Mn(quinolonato)2(phen)]. The crystal structures of [KMn(oxo)3(MeOH)3] and [Mn(erx)2(phen)], exhibiting a 1D polymeric and a mononuclear structure, respectively, have been determined by X-ray crystallography. In these complexes, the deprotonated bidentate quinolonato ligands are coordinated to manganese(II) ion through the pyridone oxygen and a carboxylato oxygen. All complexes can act as potential antibacterial agents with [Mn(erx)2(phen)] exhibiting the most pronounced antimicrobial activity against five different microorganisms. Interaction of the complexes with calf-thymus DNA (CT DNA), studied by UV spectroscopy, has shown that they bind to CT DNA. Competitive study with ethidium bromide (EB) has shown that all complexes can displace the DNA-bound EB indicating their binding to DNA in strong competition with EB. Intercalative binding mode is proposed for the interaction of the complexes with CT DNA and has also been verified by DNA solution viscosity measurements and cyclic voltammetry. DNA electrophoretic mobility experiments suggest that [Mn(erx)2(phen)] binds strongly to supercoiled pDNA and to linearized pDNA possibly by an intercalative manner provoking double-stranded cleavage reflecting in a nuclease-like activity. The complexes exhibit good binding propensity to human or bovine serum albumin protein showing relatively high binding constant values. The binding constants of the complexes towards CT DNA and albumins have been compared to their corresponding zinc(II) and nickel(II) complexes. PMID:23353085
Zampakou, Marianthi; Akrivou, Melpomeni; Andreadou, Eleni G; Raptopoulou, Catherine P; Psycharis, Vassilis; Pantazaki, Anastasia A; Psomas, George
Long-chain alkanoylcholines, a new category of soft antimicrobial agents that are enzymatically degradable.
A new category of amphiphilic hydrolyzable quaternary ammonium compounds with rapid and high levels of antimicrobial activity was studied. The compounds, alkanoylcholines with hydrocarbon chains of 10 to 14 carbon atoms, are hydrolyzed by butyrylcholine esterase, which is present in human serum and mucosal membranes. The hydrolysis products are common components of human metabolism. Alkanoylcholines were tested and found to be active against gram-negative and gram-positive bacteria as well as yeasts. The microbicidal activities of the alkanoylcholines were comparable to the activities of the stable quaternary ammonium compounds of corresponding chain length and increased with an increasing number of carbon atoms. The compounds were also found to be hydrolyzed by enzymes present in certain microorganisms. The degradation was achieved after reaching the microbicidal effect.
Ahlstrom, B; Chelminska-Bertilsson, M; Thompson, R A; Edebo, L
Synthesis and biological evaluation of novel series of aminopyrimidine derivatives as urease inhibitors and antimicrobial agents.
A novel series of carbazole substituted aminopyrimidines (5a-p) were synthesized and screened for their in vitro urease inhibition and antimicrobial activity. Among the compounds, 4-(2,4-dichlorophenyl)-6-(9-methyl-9H-carbazol-3-yl)-pyrimidin-2-amine (5i) was found to be the most potent showing urease inhibitory activity with an IC50 value 19.4 ± 0.43 µM. Compounds 5c, 5g, 5j and 5o showed good activity against all selected bacterial strains and compounds 5b, 5c, 5m and 5o showed good activity against selected fungal strains. All the compounds were subjected for ADME predictions by computational method. PMID:23230954
Adsul, Laxman K; Bandgar, Babasaheb P; Chavan, Hemant V; Jalde, Shivkumar S; Dhakane, Valmik D; Shirfule, Amol L
Poly(ethylene imine)s as antimicrobial agents with selective activity.
We report the structure-activity relationship in the antimicrobial activity of linear and branched poly(ethylene imine)s (L- and B-PEIs) with a range of molecular weights (MWs) (500-12,000). Both L- and B-PEIs displayed enhanced activity against Staphylococcus aureus over Escherichia coli. Both B- and L-PEIs did not cause any significant permeabilization of E. coli cytoplasmic membrane. L-PEIs induced depolarization of S. aureus membrane although B-PEIs did not. The low MW B-PEIs caused little or no hemolysis while L-PEIs are hemolytic. The low MW B-PEIs are less cytotoxic to human HEp-2 cells than other PEIs. However, they induced significant cell viability reduction after 24 h incubation. The results presented here highlight the interplay between polymer size and structure on activity. PMID:22865776
Gibney, Katherine A; Sovadinova, Iva; Lopez, Analette I; Urban, Michael; Ridgway, Zachary; Caputo, Gregory A; Kuroda, Kenichi
Design and synthesis of spiro[indole-thiazolidine]spiro[indole-pyrans] as antimicrobial agents.
A series of novel spiro[indole-thiazolidine]spiro[indole-pyran] derivatives were synthesized from N-(bromoalkyl)indol-2,3-diones via monospiro-bisindole intermediates; the two indole nuclei being connected via N-(CH(2))(n)-N linker. Synthesized compounds were evaluated for their antimicrobial activities in vitro against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Staphylococcus epidermis), four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumonia) as well as four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, and Candida albicans) using Cup plate method. Bis spiro-indoles exhibited stronger antibacterial and antifungal efficiency than their corresponding mono spiro-indoles. Compound 10e, the most active derivative was shown to inhibit the growth of all bacterial strains and two fungal strains (A. niger and C. albicans). PMID:21782421
Sakhuja, Rajeev; Panda, Siva S; Khanna, Leena; Khurana, Shilpi; Jain, Subhash C
Screening for antimicrobial activity of ten medicinal plants used in Colombian folkloric medicine: A possible alternative in the treatment of non-nosocomial infections
Background The antimicrobial activity and Minimal Inhibitory Concentration (MIC) of the extracts of Bidens pilosa L., Bixa orellana L., Cecropia peltata L., Cinchona officinalis L., Gliricidia sepium H.B. & K, Jacaranda mimosifolia D.Don, Justicia secunda Vahl., Piper pulchrum C.DC, P. paniculata L. and Spilanthes americana Hieron were evaluated against five bacteria (Staphylococcus aureus, Streptococcus ? hemolític, Bacillus cereus, Pseudomonas aeruginosa, and Escherichia coli), and one yeast (Candida albicans). These plants are used in Colombian folk medicine to treat infections of microbial origin. Methods Plants were collected by farmers and traditional healers. The ethanol, hexane and water extracts were obtained by standard methods. The antimicrobial activity was found by using a modified agar well diffusion method. All microorganisms were obtained from the American Type Culture Collection (ATCC). MIC was determined in the plant extracts that showed some efficacy against the tested microorganisms. Gentamycin sulfate (1.0 ?g/ml), clindamycin (0.3 ?g/ml) and nystatin (1.0 ?g/ml) were used as positive controls. Results The water extracts of Bidens pilosa L., Jacaranda mimosifolia D.Don, and Piper pulchrum C.DC showed a higher activity against Bacillus cereus and Escherichia coli than gentamycin sulfate. Similarly, the ethanol extracts of all species were active against Staphylococcus aureus except for Justicia secunda. Furthermore, Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC presented the lowest MICs against Escherichia coli (0.8, 0.6 and 0.6 ?g/ml, respectively) compared to gentamycin sulfate (0.9 8g/ml). Likewise, Justicia secunda and Piper pulchrum C.DC showed an analogous MIC against Candida albicans (0.5 and 0.6 ?g/ml, respectively) compared to nystatin (0.6 ?g/ml). Bixa orellana L, exhibited a better MIC against Bacillus cereus (0.2 ?g/ml) than gentamycin sulfate (0.5 ?g/ml). Conclusion This in vitro study corroborated the antimicrobial activity of the selected plants used in folkloric medicine. All these plants were effective against three or more of the pathogenic microorganisms. However, they were ineffective against Streptococcus ? hemolytic and Pseudomonas aeruginosa. Their medicinal use in infections associated with these two species is not recommended. This study also showed that Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC could be potential sources of new antimicrobial agents.
Rojas, Jhon J; Ochoa, Veronica J; Ocampo, Saul A; Munoz, John F
Medicinal plants from Peru: a review of plants as potential agents against cancer.
Natural products have played a significant role in drug discovery and development especially for agents against cancer and infectious disease. An analysis of new and approved drugs for cancer by the United States Food and Drug Administration over the period of 1981-2002 showed that 62% of these cancer drugs were of natural origin. Natural compounds possess highly diverse and complex molecular structures compared to small molecule synthetic drugs and often provide highly specific biological activities likely derived from the rigidity and high number of chiral centers. Ethnotraditional use of plant-derived natural products has been a major source for discovery of potential medicinal agents. A number of native Andean and Amazonian medicines of plant origin are used as traditional medicine in Peru to treat different diseases. Of particular interest in this mini-review are three plant materials endemic to Peru with the common names of Cat's claw (Uncaria tomentosa), Maca (Lepidium meyenii), and Dragon's blood (Croton lechleri) each having been scientifically investigated for a wide range of therapeutic uses including as specific anti-cancer agents as originally discovered from the long history of traditional usage and anecdotal information by local population groups in South America. Against this background, we present an evidence-based analysis of the chemistry, biological properties, and anti-tumor activities for these three plant materials. In addition, this review will discuss areas requiring future study and the inherent limitations in their experimental use as anti-cancer agents. PMID:17017852
Gonzales, Gustavo F; Valerio, Luis G
Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.
Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection. PMID:25037402
Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M
Anticancer and antimicrobial activities of some antioxidant-rich cameroonian medicinal plants.
Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin-Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC(50) values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin. PMID:23409075
Tamokou, Jean de Dieu; Chouna, Jean Rodolphe; Fischer-Fodor, Eva; Chereches, Gabriela; Barbos, Otilia; Damian, Grigore; Benedec, Daniela; Duma, Mihaela; Efouet, Alango Pépin Nkeng; Wabo, Hippolyte Kamdem; Kuiate, Jules Roger; Mot, Augustin; Silaghi-Dumitrescu, Radu
Anticancer and Antimicrobial Activities of Some Antioxidant-Rich Cameroonian Medicinal Plants
Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin–Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC50 values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin.
Tamokou, Jean de Dieu; Chouna, Jean Rodolphe; Fischer-Fodor, Eva; Chereches, Gabriela; Barbos, Otilia; Damian, Grigore; Benedec, Daniela; Duma, Mihaela; Efouet, Alango Pepin Nkeng; Wabo, Hippolyte Kamdem; Kuiate, Jules Roger; Mot, Augustin; Silaghi-Dumitrescu, Radu
Phytochemical compounds and antimicrobial activity of three medicinal plants (Alchornea hirtella, Morinda geminata and Craterispermum laurinum) from Sierra Leone
Petroleum ether, acetone, ethanolic and aqueous crude extracts of various plant organs of Alchornea hirtella, Morinda geminata and Craterispermum laurinum used in Sierra Leone exhibited variable degree of antimicrobial activity against four bacterial species. Compared with the standard drug ciprofloxacin, the extracts exhibited low to moderate antibacterial activity. Generally, the tested microorganisms were resistant to the petroleum ether and acetone
Lahai Koroma
Characterization of antimicrobial resistance and virulence genotypes of Enterococcus faecalis recovered from a pork processing plant.
The objective of this study was to assess the antimicrobial resistance and virulence genotypes of Enterococcus faecalis isolated from samples obtained from a commercial pork processing plant. A total of 200 samples were randomly obtained from carcasses after bleeding (BC; 50 samples) and pasteurization (PC; 100 samples) and from retail pork products (RP; 50 samples). One isolate from each E. faecalis -positive sample was analyzed for antimicrobial susceptibility and characterized using a enterococcal microarray for analysis of resistance and virulence genes. E. faecalis was isolated from 79.5% of BC samples, 2% of PC samples, and 72.7% of RP samples. Resistance to the clinically important drugs ciprofloxacin (one isolate each from BC and RP samples) and daptomycin (one isolate each from PC and RP samples) was found. Multiresistance (to five or more antimicrobials) was more common in E. faecalis isolates from BC (77.4% of isolates) samples than those from PC (25%) and RP (37.6%) samples. Resistance to kanamycin (43.5%) and streptomycin (69.2%) was noted mostly in E. faecalis from BC samples. The most common resistance genes (>5% prevalence) found in E. faecalis were those for aminoglycosides (aac(6), aphA3, and aadE), macrolides-lincosamide (ermB, ermA, sat(4), and linB), and tetracyclines (tetL, tetM, and tetO ). The virulence genes expressing adhesion (ace, efaAfs, and agrBfs), gelatinase (gelE), and pheromone (cAM, ccF10, cob, and cpd1) factors were found in the majority of isolates. Significant associations were found between resistance and virulence genes, suggesting their possible relationship. These data suggest that carcasses entering the final product processing area are mostly free of E. faecalis but are recontaminated with antimicrobial-resistant strains during processing. The source of these contaminants remains to be identified; however, these results underscore the importance of E. faecalis as a reservoir of resistance and virulence genes. PMID:22856575
Aslam, Mueen; Diarra, Moussa S; Masson, Luke
Antimicrobial activity of {gamma}-thionin-like soybean SE60 in E. coli and tobacco plants
The SE60, a low molecular weight, sulfur-rich protein in soybean, is known to be homologous to wheat {gamma}-purothionin. To elucidate the functional role of SE60, we expressed SE60 cDNA in Escherichia coli and in tobacco plants. A single protein band was detected by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) after anti-FLAG affinity purification of the protein from transformed E. coli. While the control E. coli cells harboring pFLAG-1 showed standard growth with Isopropyl {beta}-D-1-thiogalactopyranoside (IPTG) induction, E. coli cells expressing the SE60 fusion protein did not grow at all, suggesting that SE60 has toxic effects on E. coli growth. Genomic integration and the expression of transgene in the transgenic tobacco plants were confirmed by Southern and Northern blot analysis, respectively. The transgenic plants demonstrated enhanced resistance against the pathogen Pseudomonas syringae. Taken together, these results strongly suggest that SE60 has antimicrobial activity and play a role in the defense mechanism in soybean plants.
Choi, Yeonhee [School of Biological Sciences, Seoul National University, Seoul 151-747 (Korea, Republic of)], E-mail: email@example.com; Choi, Yang Do [Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921 (Korea, Republic of); Lee, Jong Seob [School of Biological Sciences, Seoul National University, Seoul 151-747 (Korea, Republic of)], E-mail: firstname.lastname@example.com
Molecular genetic basis of antimicrobial agent resistance in Mycobacterium tuberculosis: 1998 update
Knowledge of the molecular genetic basis of resistance to antituberculous agents has advanced rapidly since we reviewed this topic 3 years ago. Virtually all isolates resistant to rifampin and related rifamycins have a mutation that alters the sequence of a 27-amino-acid region of the beta subunit of ribonucleic acid (RNA) polymerase. Resistance to isoniazid (INH) is more complex. Many resistant
S. Ramaswamy; J. M. Musser
Effects of carbadox, a synthetic antimicrobial agent, on bile acid metabolism in the domestic pig
Radiolabeled chenodeoxycholic acid (CDC) was infused into the hepatic portal vein (HP) and fluctuations of the plasma radioactivities of CDC and its metabolites were monitored in young unrestrained pigs. There was a significant difference in the plasma radioactivity between the morning and evening meals from both vena cava and portal vein plasma samples. To study the effects of an antimicrobial feed additive on bile acid metabolism, carbadox (CX) was added to a 19.5% corn-soybean ration and fed to young pigs. CX at 58 ppm affected apparent clearance of CDC from the HP blood. The plasma concentrations of the bile acids were higher in the animals fed CX. Plasma fluctuations of the bile acids in response to meals showed that the plasma bile acid concentrations following feeding at 1600 hours were greater than those following feeding at 0800 hours. The rate of excretion of the bile acids in the feces was increased and biological half-life of CDC decreased to 5.7 in the CX-fed pigs from 6.4 days in the controls. The feeding of CX did not significantly affect the activity of cholesterol 7..cap alpha..-hydroxylase (CH-7..cap alpha..), the rate-limiting enzyme for bile acid synthesis.
Tracy, J.D.
Azoles and bis-azoles: synthesis and biological evaluation as antimicrobial and anti-cancer agents.
Novel hydrazonoyl halides 3, 5 and bis-hydrazonoyl halides 7, 9 were synthesized. The synthetic utility of bis-hydrazonoyl halide 7 was explored to prepare novel bis-azole 13 with antipyrine moiety. On the other hand, [1,3,4]thiadiazol-2(3H)-ylidene 17 and thiazol-2(3H)-ylidene 21 derivatives, with antipyrine moiety, were prepared from the reaction of 3-mercapto-3-(phenylamino)acrylamide derivative 10 with N-phenyl benzenecarbohydrazonoyl chloride (14) and 3-(2-bromoacetyl)-2H-chromen-2-one (18), respectively. The structures of the isolated products were confirmed by spectral data (IR, (1)H-NMR, (13)C-NMR, MS) and elemental analyses. The anti-cancer activitiy of the synthesized products against the colon carcinoma (HCT) cell line was determined and the results revealed promising activity of compound 3. In addition, the antimicrobial activity of some selected products was evaluated. The results proclaimed that compounds 9, 17, and 21 have high antibacterial activity against Gram-positive bacteria (SA, BS) and Gram-negative bacteria (PA, EC). PMID:23649193
Kheder, Nabila Abdelshafy; Riyadh, Sayed Mohamed; Asiry, Ahlam Maade
Preserving ignitable liquid residues on soil using Triclosan as an anti-microbial agent.
When a fire is suspected to be intentionally set, fire debris samples can be collected and analyzed for ignitable liquid residues (ILRs). In some cases, samples will contain highly organic substrates such as soil or rotting wood. These substrates will contain a high bacterial load, which can result in systematic and irreversible damage to the ILR due to microbial degradation. This paper explores ways to preserve ILR by sterilizing fire debris samples without interfering with their subsequent analysis. There are many methods reported in the literature for sterilizing soil, such as freezing, irradiation, autoclaving, and various chemical fumigation techniques. However, these methods either do not kill all bacterial species, cannot be easily applied in the field or would interfere with the analysis of the ILRs. For this work, various anti-microbial compounds including triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) were tested for their efficacy at killing bacteria present in the soil. Triclosan was highly effective in qualitative growth studies and was therefore used to measure bacterial growth (or lack thereof) by spectroscopic analysis as well as passive headspace analysis. These experiments showed that triclosan was able to sterilize soil samples in less than 60s, maintain their sterility for at least 77h and preserve gasoline residues on a soil matrix for at least 30 days. PMID:24769222
Turner, Dee A; Goodpaster, John V
Essential oil from Zanthoxylum tingoassuiba loaded into multilamellar liposomes useful as antimicrobial agents.
Zanthoxylum tingoassuiba essential oil (EO) is a complex mixture of organic compounds among which methyl-N-methylanthranilate and sesquiterpene alcohol alpha-bisabolol represent the main compounds. The essential oil antimicrobial activity was studied against bacteria and fungi cells by diffusion disk method and significant activity was observed against S. aureus, S. aureus isolated multi-resistant and the dermathophyte fungi. Essential oil from Zanthoxylum tingoassuiba loaded into DPPC multilamellar liposomes (MLV) was successfully produced through a thin film hydration method with mean diameter of 9.37 +/- 4.69 microm. The EO-loaded liposomes showed adequate sphericity and narrower size distribution than empty liposomes. Results also showed that Zanthoxylum tingoassuiba essential oil can be incorporated in appreciable amounts (43.7 +/- 6.0%) in the prepared vesicular dispersions. A strong interaction between essential oil and lipid bilayer was indicated by a significant decrease in T(m) of the EO-loaded liposomes related to empty vesicles. Essential oil showed incomplete release profile from liposomes, suggesting that EO-loaded liposomes will be useful in pharmaceutical applications to enhance essential oil targeting to cells. PMID:19888877
Detoni, C B; Cabral-Albuquerque, E C M; Hohlemweger, S V A; Sampaio, C; Barros, T F; Velozo, E S
Investigating the suitability of the Calgary Biofilm Device for assessing the antimicrobial efficacy of new agents.
This study investigated the suitability of the Calgary Biofilm Device (CBD), originally designed as a test surrogate for indwelling medical devices, for assessing the efficacy of antimicrobials developed for food and food contact surface disinfection applications. The conditions for the development of uniform biofilms from pure and mixed bacterial cultures of wild type Escherichia coli and Listeria innocua were optimized. We were able to recover approximately 2 x 10(6) colony forming units (CFU) from the biofilms formed on the individual pegs of the device in 24 h. Further, the parameters for the consistent release of the cells from the biofilms were optimized; test showed that the number of cells released was uniform and reproducible. The consistency and reproducibility of the biofilms formed on the pegs was evaluated using scanning electron microscopy and by plate count method. The efficacies of disinfectants on cells residing in biofilms versus planktonic cells were compared. For both species, higher concentrations of disinfectants were needed to eliminate attached cells as compared with planktonic cells. This study establishes the value of the CBD for generating consistent biofilms from either pure or mixed cultures. These biofilms can be used to assess efficacies of disinfectants against cells that have colonized the surfaces of foods and food-processing equipment. Such a system could serve as a standard surrogate for evaluating new disinfectants designed to reduce or eliminate biofilms from food-contact surfaces. PMID:16256346
Ali, Laila; Khambaty, Farukh; Diachenko, Gregory
Potential antimicrobial agents for the treatment of multidrug-resistant tuberculosis.
Treatment of multidrug-resistant (MDR) tuberculosis (TB) is challenging because of the high toxicity of second-line drugs and the longer treatment duration than for drug-susceptible TB patients. In order to speed up novel treatment for MDR-TB, we suggest considering expanding the indications of already available drugs. Six drugs with antimicrobial activity (phenothiazine, metronidazole, doxycycline, disulfiram, tigecycline and co-trimoxazole) are not listed in the World Health Organization guidelines on MDR-TB treatment but could be potential candidates for evaluation against Mycobacterium tuberculosis. A systematic review was conducted to evaluate antituberculous activity of these drugs against M. tuberculosis. We searched PubMed, Google Scholar and Embase for English articles published up to December 31, 2012. We reviewed in vitro, in vivo and clinical antituberculous activity of these drugs in addition to pharmacokinetics and side-effects. Of the drugs effective against actively replicating M. tuberculosis, co-trimoxazole seems to be the most promising, because of its consistent pharmacokinetic profile, easy penetration into tissue and safety profile. For the dormant state of TB, thioridazine may play a potential role as an adjuvant for treatment of MDR-TB. A strategy consisting of pharmacokinetic/pharmacodynamic studies, dose finding and phase III studies is needed to explore the role of these drugs in MDR-TB treatment. PMID:23988774
Alsaad, Noor; Wilffert, Bob; van Altena, Richard; de Lange, Wiel C M; van der Werf, Tjip S; Kosterink, Jos G W; Alffenaar, Jan-Willem C
Antimicrobial Stewardship Programs
The development of antimicrobial agents represents one of the most significant achievements in medicine during the past century. However, the emergence of antimicrobial resistance combined with the downturn in the development of new antimicrobial agents in the pharmaceutical industry poses unanticipated challenges in the effective management of infection. The issue of how we can most effectively utilize these invaluable resources, antimicrobials, in the face of infections that are ever more difficult to treat arises. This issue serves as the fundamental basis for the concept of antimicrobial stewardship, the topic of this minireview.
Leuthner, Kimberly D.
In vitro antimicrobial activity of plants used in Cambodian traditional medicine.
The purpose of the present study was to screen 27 plant species used in the traditional medicine of Cambodia for in vitro antibacterial and antifungal activities. Thirty-three methanolic extracts were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans. Screened by disk diffusion assay, the extracts showed antimicrobial activity especially on Gram-positive bacteria. None of the crude methanolic extracts showed activity against P. aeruginosa. Twenty-five selected extracts were evaluated using a micro-dilution test. Harrisonia perforata (roots) and Hymenodictyon excelsum (bark) exhibited a bactericidal effect against S. aureus at a concentration of 500 microg/ml. Azadirachta indica (bark), Harrisonia perforata (roots and stem) and Shorea obtusa (roots) exhibited a bactericidal effect against M. smegmatis at 250 microg/ml. PMID:17963325
Chea, Aun; Jonville, Marie-Caroline; Bun, Sok-Siya; Laget, Michčle; Elias, Riad; Duménil, Gérard; Balansard, Guy
Antimicrobial activity of extracts of herbal plants used in the traditional medicine of Jordan.
Petroleum ether, ethanol, butanol, and aqueous crude extracts of the whole aerial parts of nine plants exhibited variable degrees of antimicrobial activity against four bacterial and three fungal species. Methanol and hexane extracts did not show any activity. Compared with standard antibiotics, extracts had low to moderate activity. The activity spectrum is wide against gram-positive and negative bacteria as well as fungi tested. However, the butanol extracts at 4 mg/disc of Ononis spinosa (OS), Bryonia syriaca (BS) had high moderate antifungal activity against Aspergillus flavus, Fusarium moniliforme and Candida albicans relative to miconazole nitrate at 40 microg/disc. Furthermore, higher antibacterial activity was observed though low to moderate compared with streptomycin and very comparable with chloramphenicol. Cyclaman persicum (CP) petroleum ether extracts only exhibited pronounced antibacterial activity. PMID:10363844
Mahasneh, A M; El-Oqlah, A A
Engineered plant biomass particles coated with bioactive agents
Plant biomass particles coated with a bioactive agent such as a fertilizer or pesticide, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.
Dooley, James H; Lanning, David N
Synergy in a medicinal plant: Antimicrobial action of berberine potentiated by 5?-methoxyhydnocarpin, a multidrug pump inhibitor
Multidrug resistance pumps (MDRs) protect microbial cells from both synthetic and natural antimicrobials. Amphipathic cations are preferred substrates of MDRs. Berberine alkaloids, which are cationic antimicrobials produced by a variety of plants, are readily extruded by MDRs. Several Berberis medicinal plants producing berberine were found also to synthesize an inhibitor of the NorA MDR pump of a human pathogen Staphylococcus aureus. The inhibitor was identified as 5?-methoxyhydnocarpin (5?-MHC), previously reported as a minor component of chaulmoogra oil, a traditional therapy for leprosy. 5?-MHC is an amphipathic weak acid and is distinctly different from the cationic substrates of NorA. 5?-MHC had no antimicrobial activity alone but strongly potentiated the action of berberine and other NorA substrates against S. aureus. MDR-dependent efflux of ethidium bromide and berberine from S. aureus cells was completely inhibited by 5?-MHC. The level of accumulation of berberine in the cells was increased strongly in the presence of 5?-MHC, indicating that this plant compound effectively disabled the bacterial resistance mechanism against the berberine antimicrobial.
Stermitz, Frank R.; Lorenz, Peter; Tawara, Jeanne N.; Zenewicz, Lauren A.; Lewis, Kim
Encapsulation of the antimicrobial and immunomodulator agent nitazoxanide within polymeric micelles.
Nitazoxanide (NTZ) is a highly hydrophobic nitrothiazolyl-salicylamide that displays antimicrobial activity against a variety of parasites, anaerobic bacteria and viruses. More recently, its effectiveness in the pharmacotherapy of chronic hepatitis, the leading cause of liver cirrhosis and hepatocellular carcinoma (HCC), has been reported. On the other hand, the extremely low aqueous solubility of the drug challenges its administration by different routes. The present work explored for the first time the encapsulation of NTZ within pristine, lactosylated and mixed poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) polymeric micelles (PMs) of different architectures, molecular weights and hydrophilic-lipophilic balance (HLB) as a strategy to improve its aqueous solubility and to potentially target it to the liver parenchyma. The solubility was increased up to 609 times. The drug encapsulation modified the self-aggregation pattern of the different amphiphiles, resulting in a sharp growth of the micellar size. The encapsulation capacity of the lactosylated derivatives was smaller than that of the pristine counterparts, though the development of mixed PMs that combine a highly hydrophilic lactosylated amphiphile (e.g., poloxamer F127 or poloxamine T1107) that forms the micellar template and a more hydrophobic unmodified poloxamine (T904) that increases the hydrophobicity of the core resulted in the synergistic encapsulation of the drug and a substantial increase of the physical stability over time. Overall findings confirmed the extremely great versatility of the poloxamer/poloxamine mixed self-assembly systems as Trojan nanocarriers for the encapsulation of NTZ towards its targeting to the liver. PMID:24738446
Glisoni, Romina J; Sosnik, Alejandro
Thin-layer chromatographic (TLC) separations and bioassays of plant extracts to identify antimicrobial compounds.
A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth. The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions. This paper describes standard protocols for TLC and contact bioautography with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light. Zones are cut out and incubated face down onto agar inoculated with the test microorganism. Inhibitory bands are visualized by staining the agar plates with tetrazolium red. The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen. The TLC methods apply to many types of plant extracts and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species. PMID:24747583
Kagan, Isabelle A; Flythe, Michael D
Apple puree-alginate edible coating as carrier of antimicrobial agents to prolong shelf-life of fresh-cut apples
Edible coatings with antimicrobial agents can extend the shelf-life of fresh-cut fruit. The effect of lemongrass, oregano oil and vanillin incorporated in apple puree-alginate edible coatings, on the shelf-life of fresh-cut 'Fuji' apples, was investigated. Coated apples were packed in air filled polypropylene trays and wrapped with polypropylene film. Changes in headspace atmosphere, color, firmness, sensory quality and microbial growth
María A. Rojas-Graü; Rosa M. Raybaudi-Massilia; Robert C. Soliva-Fortuny; Roberto J. Avena-Bustillos; Tara H. McHugh; Olga Martín-Belloso
Susceptibility to antimicrobial agents among bovine mastitis pathogens isolated from North American dairy cattle, 2002-2010.
Approximately 8,000 isolates of Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Staphylococcus aureus, and Escherichia coli, isolated by 25 veterinary laboratories across North America between 2002 and 2010, were tested for in vitro susceptibility to beta-lactam, macrolide, and lincosamide drugs. The minimal inhibitory concentrations (MICs) of the beta-lactam drugs remained low against most of the Gram-positive strains tested, and no substantial changes in the MIC distributions were seen over time. Of the beta-lactam antimicrobial agents tested, only ceftiofur showed good in vitro activity against E. coli. The MICs of the macrolides and lincosamides also remained low against Gram-positive mastitis pathogens. While the MIC values given by 50% of isolates (MIC50) for erythromycin and pirlimycin and the streptococci were all low (?0.5 µg/ml), the MIC values given by 90% of isolates (MIC90) were higher and more variable, but with no apparent increase over time. Staphylococcus aureus showed little change in erythromycin susceptibility over time, but there may be a small, numerical increase in pirlimycin MIC50 and MIC90 values. Overall, the results suggest that mastitis pathogens in the United States and Canada have not shown any substantial changes in the in vitro susceptibility to beta-lactam, macrolide, and lincosamide drugs tested over the 9 years of the study. PMID:23907894
Lindeman, Cynthia J; Portis, Ellen; Johansen, Lacie; Mullins, Lisa M; Stoltman, Gillian A
Synthesis of 2,3,6-trideoxy sugar triazole hybrids as potential new broad spectrum antimicrobial agents.
Here, we describe a molecular hybridization inspired design and synthesis of novel 6-triazolyl 2,3,6-trideoxy sugars as promising new broad-spectrum antimicrobial agents using click chemistry in key step. These compounds showed MIC between 0.39 and 50 ?g/mL against different native and resistant bacteria and fungi with no toxicity. Among them, compound 29 was the most active molecule with MIC 0.78 ?g/mL against Staphylococcus aureus and Klebsiella pneumoniae and 3.12 ?g/mL against methicillin- and vancomycin-resistant S. aureus. Compound 26 was the most potent anti-fungal candidate with MIC 0.39 ?g/mL against Trichophyton mentagrophytes. Compound 46 was found to be promising with broad-spectrum activity against both bacterial and fungal strains. The bioinformatic studies involving bacteria's protein co-crystals prompted penicillin binding protein-2 as the most likely target of these compounds. PMID:24992075
Sharma, Smriti; Saquib, Mohammad; Verma, Saroj; Mishra, Nripendra N; Shukla, Praveen K; Srivastava, Ranjana; Prabhakar, Yenamandra S; Shaw, Arun K
Antagonism of Azole Activity against Candida albicans following Induction of Multidrug Resistance Genes by Selected Antimicrobial Agents
Antifungal azoles (e.g., fluconazole) are widely used for prophylaxis or treatment of Candida albicans infections in immunocompromised individuals, such as those with AIDS. These individuals are frequently treated with a variety of additional antimicrobial agents. Potential interactions between three azoles and 16 unrelated drugs (antiviral, antibacterial, antifungal, and antiprotozoal agents) were examined in vitro. Two compounds, tested at concentrations achievable in serum, demonstrated an antagonistic effect on azole activity against C. albicans. At fluconazole concentrations two to four times the 50% inhibitory concentration, C. albicans growth (relative to treatment with fluconazole alone) increased 3- to 18-fold in the presence of albendazole (2 ?g/ml) or sulfadiazine (50 ?g/ml). Antagonism (3- to 78-fold) of ketoconazole and itraconazole activity by these compounds was also observed. Since azole resistance has been correlated with overexpression of genes encoding efflux proteins, we hypothesized that antagonism results from drug-induced overexpression of these same genes. Indeed, brief incubation of C. albicans with albendazole or sulfadiazine resulted in a 3-to->10-fold increase in RNAs encoding multidrug transporter Cdr1p or Cdr2p. Zidovudine, trimethoprim, and isoniazid, which were not antagonistic with azoles, did not induce these RNAs. Fluphenazine, a known substrate for Cdr1p and Cdr2p, strongly induced their RNAs and, consistent with our hypothesis, strongly antagonized azole activity. Finally, antagonism was shown to require a functional Cdr1p. The possibility that azole activity against C. albicans is antagonized in vivo as well as in vitro in the presence of albendazole and sulfadiazine warrants investigation. Drug-induced overexpression of efflux proteins represents a new and potentially general mechanism for drug antagonism.
Henry, Karl W.; Cruz, M. Cristina; Katiyar, Santosh K.; Edlind, Thomas D.
General Principles of Antimicrobial Therapy
Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community.
Leekha, Surbhi; Terrell, Christine L.; Edson, Randall S.
Constitutive expression of transgenes encoding derivatives of the synthetic antimicrobial peptide BP100: impact on rice host plant fitness
Background The Biopeptide BP100 is a synthetic and strongly cationic ?-helical undecapeptide with high, specific antibacterial activity against economically important plant-pathogenic bacteria, and very low toxicity. It was selected from a library of synthetic peptides, along with other peptides with activities against relevant bacterial and fungal species. Expression of the BP100 series of peptides in plants is of major interest to establish disease-resistant plants and facilitate molecular farming. Specific challenges were the small length, peptide degradation by plant proteases and toxicity to the host plant. Here we approached the expression of the BP100 peptide series in plants using BP100 as a proof-of-concept. Results Our design considered up to three tandemly arranged BP100 units and peptide accumulation in the endoplasmic reticulum (ER), analyzing five BP100 derivatives. The ER retention sequence did not reduce the antimicrobial activity of chemically synthesized BP100 derivatives, making this strategy possible. Transformation with sequences encoding BP100 derivatives (bp100der) was over ten-fold less efficient than that of the hygromycin phosphotransferase (hptII) transgene. The BP100 direct tandems did not show higher antimicrobial activity than BP100, and genetically modified (GM) plants constitutively expressing them were not viable. In contrast, inverted repeats of BP100, whether or not elongated with a portion of a natural antimicrobial peptide (AMP), had higher antimicrobial activity, and fertile GM rice lines constitutively expressing bp100der were produced. These GM lines had increased resistance to the pathogens Dickeya chrysanthemi and Fusarium verticillioides, and tolerance to oxidative stress, with agronomic performance comparable to untransformed lines. Conclusions Constitutive expression of transgenes encoding short cationic ?-helical synthetic peptides can have a strong negative impact on rice fitness. However, GM plants expressing, for example, BP100 based on inverted repeats, have adequate agronomic performance and resistant phenotypes as a result of a complex equilibrium between bp100der toxicity to plant cells, antimicrobial activity and transgene-derived plant stress response. It is likely that these results can be extended to other peptides with similar characteristics.
Comparative susceptibilities of various AIDS-associated and human urogenital tract mycoplasmas and strains of Mycoplasma pneumoniae to 10 classes of antimicrobial agent in vitro.
The susceptibilities of 40 strains of various Mycoplasma species to 10 classes of antimicrobial agents were compared in vitro by a broth microdilution method. The strains tested comprised 20 strains of four AIDS-associated species--M. penetrans (1 strain), M. fermentas (5 strains), M. pirum (6 strains) and M. genitalium (8 strains)--nine strains of the urogenital tract species M. hominis and 11 strains of M. pneumoniae. The results demonstrated wide variation in the susceptibilities of the different Mycoplasma spp. to different classes of antimicrobial agent. All the mycoplasmas were susceptible or highly susceptible to the fluoroquinolones, with sparfloxacin the most active, and to the diterpine antibiotic tiamulin. M. pneumoniae and M. genitalium strains were also highly susceptible to the macrolides, particularly azithromycin and had similar antibiotic susceptibility patterns to most other antimicrobial agents. However, all strains of M. genitalium were resistant to streptomycin (MIC 250->500 mg/L) whereas all M. pneumoniae isolates, except the MAC strain, were susceptible (MICs 1.25-12.5 mg/L). M. pirum isolates varied considerably in their susceptibility to macrolides (MIC range versus azithromycin 0.0025->100 mg/L). M. fermentans strains were susceptible to the tetracyclines, lincosamides and mupirocin, but varied in susceptibility to aminoglycosides. Most M. hominis strains were susceptible to the tetracyclines and all were susceptible to clindamycin and mupirocin. M. penetrans GTU 54 was susceptible to azithromycin, the tetracyclines and lincosamides as well as to the fluoroquinolones and tiamulin. PMID:9856648
Hannan, P C
In vitro activity of BAY y 3118, and nine other antimicrobial agents against anaerobic bacteria.
The antibacterial activity of BAY y 3118, a new chlorofluoroquinolone, was determined against 257 strains of anaerobic bacteria and compared with the activities of ofloxacin, ciprofloxacin, sparfloxacin, imipenem, cefoxitin, clindamycin, chloramphenicol, metronidazole, and ornidazole. Overall, BAY y 3118 was the most active agent tested against the Bacteroides fragilis group. Its activity (MIC90, 0.5 mg/L) was 16-fold lower than that of sparfloxacin (MIC90, 8 mg/L), and more than 100-fold lower than that of ofloxacin (MIC90, 64 mg/L) and ciprofloxacin (MIC90, 128 mg/L) against the group. No strains belonging to this group were resistant to metronidazole (MICs range, 0.12-2 mg/L) and ornidazole (MICs range, 0.12-4 mg/L). BAY y 3118 was more active than those quinolones against Prevotella and Porphyromonas spp., Fusobacterium spp., Clostridium perfringens and C. difficile (MIC90, 0.12, 0.06, 0.12 and 0.25 mg/L, respectively). The activity of BAY y 3118 against Peptostreptococcus spp. (MIC90, 1 mg/L) was slightly lower than that of the other Gram-positive bacteria tested. In general, BAY y 3118 was more active than cefoxitin, and it was superior to antianaerobic chemical agents like metronidazole, ornidazole and clindamycin. Pharmacokinetic and clinical trials are required to define the role of BAY y 3118 in the treatment of anaerobic infections. PMID:7562012
García-Rodríguez, J A; García-Sánchez, J E; Trujillano-Martín, I; García-Sánchez, E; García-García, M I; Fresnadillo-Martínez, M J
The bee diseases American and European foulbrood and nosemosis can be treated with anti-infectious agents. However, in the EU and the USA the use of these agents in beekeeping is strictly regulated due to the lack of tolerance (e.g. Maximum Residue Limit) for residues of antibiotics and chemotherapeutics in honey. This article reviews the literature dealing with antimicrobials of interest in apiculture, stability of these antimicrobials in honey, and disposition of the antimicrobials in honeybee hives. PMID:22342494
Reybroeck, Wim; Daeseleire, Els; De Brabander, Hubert F; Herman, Lieve
The antimicrobial effectiveness of operative-site preparative agents: a microbiological and clinical study.
Eight wound preparative agents (one triclosan compound, one hexachlorophene compound, and six iodophors) were evaluated under actual operating-room conditions for efficacy in de-germing the operative site prior to the performance of 310 total hip arthroplasties. All of the preparations tested achieved a significant reduction (p less than or equal to 0.001) of indigenous skin microflora compared with the pre-scrub level in both the post-scrub and the postoperative cultures. Two iodophors, when applied as sprays, demonstrated excellent bactericidal action, were less time-consuming and easier to use than the compounds that were applied as scrubs, and did not alter the low (0.42 per cent) infection rate that we have recorded over a period of four years. PMID:7391106
Ritter, M A; French, M L; Eitzen, H E; Gioe, T J
Comparative in vitro activity of several antimicrobial agents against selected clinical isolates.
A comparison between the in vitro activities of ceftazidime, cefotaxime, ceftriaxone, ampicillin, piperacillin, gentamicin, tobramycin and netilmicin was performed on selected clinical isolates. The activity of the agents was assessed by means of minimum inhibitory concentration determinations, and time-kill studies. The third generation cephalosporins were active against all members of the Enterobacteriaceae excluding some Enterobacter species. Their activity against these bacteria was generally comparable and greater than that of piperacillin. Netilmicin was the most active of the aminoglycosides tested against members of the Enterobacteriaceae; however, aminoglycoside-resistant strains were encountered. Ceftazidime was the most active of the third generation cephalosporins against the non-fermenters (e.g. Pseudomonas and Acinetobacter spp), its inhibitory activity also being greater than that of piperacillin. Using a time-kill study, ceftazidime also demonstrated greater bactericidal activity than piperacillin against an isolate of Pseudomonas aeruginosa. The aminoglycoside demonstrating the greatest activity against the non-fermenters was tobramycin. PMID:2109875
Liebowitz, L D; Saunders, J; Chalkley, L J; Koornhof, H J
New Type of Antimicrobial Protein Produced by the Plant Pathogen Clavibacter michiganensis subsp. michiganensis
It has previously been shown that the tomato pathogen Clavibacter michiganensis subsp. michiganensis secretes a 14-kDa protein, C. michiganensis subsp. michiganensis AMP-I (CmmAMP-I), that inhibits growth of Clavibacter michiganensis subsp. sepedonicus, the causal agent of bacterial ring rot of potato. Using sequences obtained from tryptic fragments, we have identified the gene encoding CmmAMP-I and we have recombinantly produced the protein with an N-terminal intein tag. The gene sequence showed that CmmAMP-I contains a typical N-terminal signal peptide for Sec-dependent secretion. The recombinant protein was highly active, with 50% growth inhibition (IC50) of approximately 10 pmol, but was not toxic to potato leaves or tubers. CmmAMP-I does not resemble any known protein and thus represents a completely new type of bacteriocin. Due to its high antimicrobial activity and its very narrow inhibitory spectrum, CmmAMP-1 may be of interest in combating potato ring rot disease.
Liu, Zhanliang; Ma, Ping; Holtsmark, Ingrid; Skaugen, Morten; Eijsink, Vincent G. H.
The use of resazurin as a novel antimicrobial agent against Francisella tularensis.
The highly infectious and deadly pathogen, Francisella tularensis, is classified by the CDC as a Category A bioterrorism agent. Inhalation of a single bacterium results in an acute pneumonia with a 30-60% mortality rate without treatment. Due to the prevalence of antibiotic resistance, there is a strong need for new types of antibacterial drugs. Resazurin is commonly used to measure bacterial and eukaryotic cell viability through its reduction to the fluorescent product resorufin. When tested on various bacterial taxa at the recommended concentration of 44 ?M, a potent bactericidal effect was observed against various Francisella and Neisseria species, including the human pathogens type A F. tularensis (Schu S4) and N. gonorrhoeae. As low as 4.4 ?M resazurin was sufficient for a 10-fold reduction in F. tularensis growth. In broth culture, resazurin was reduced to resorufin by F. tularensis. Resorufin also suppressed the growth of F. tularensis suggesting that this compound is the biologically active form responsible for decreasing the viability of F. tularensis LVS bacteria. Replication of F. tularensis in primary human macrophages and non-phagocytic cells was abolished following treatment with 44 ?M resazurin indicating this compound could be an effective therapy for tularemia in vivo. PMID:24367766
Schmitt, Deanna M; O'Dee, Dawn M; Cowan, Brianna N; Birch, James W-M; Mazzella, Leanne K; Nau, Gerard J; Horzempa, Joseph
The use of resazurin as a novel antimicrobial agent against Francisella tularensis
The highly infectious and deadly pathogen, Francisella tularensis, is classified by the CDC as a Category A bioterrorism agent. Inhalation of a single bacterium results in an acute pneumonia with a 30–60% mortality rate without treatment. Due to the prevalence of antibiotic resistance, there is a strong need for new types of antibacterial drugs. Resazurin is commonly used to measure bacterial and eukaryotic cell viability through its reduction to the fluorescent product resorufin. When tested on various bacterial taxa at the recommended concentration of 44 ?M, a potent bactericidal effect was observed against various Francisella and Neisseria species, including the human pathogens type A F. tularensis (Schu S4) and N. gonorrhoeae. As low as 4.4 ?M resazurin was sufficient for a 10-fold reduction in F. tularensis growth. In broth culture, resazurin was reduced to resorufin by F. tularensis. Resorufin also suppressed the growth of F. tularensis suggesting that this compound is the biologically active form responsible for decreasing the viability of F. tularensis LVS bacteria. Replication of F. tularensis in primary human macrophages and non-phagocytic cells was abolished following treatment with 44 ?M resazurin indicating this compound could be an effective therapy for tularemia in vivo.
Schmitt, Deanna M.; O'Dee, Dawn M.; Cowan, Brianna N.; Birch, James W.-M.; Mazzella, Leanne K.; Nau, Gerard J.; Horzempa, Joseph
Synthesis of a new class of antimicrobial agents incorporating the indolin-2-one moiety.
New furanone derivatives incorporating the indolin-2-one moiety 3 were prepared via the Perkin reaction of isatins 1 with aroylpropionic acids 2 under conventional conditions or microwave irradiation. A series of functionally heterocyclic derivatives (e.g., pyridazines, pyrroles, and sulfonamides) incorporating the indolin-2-one moiety was achieved via reaction of 3 with different reagents under microwave irradiation conditions. The newly synthesized compounds were characterized on the basis of FTIR, (1)H, (13)C NMR and mass spectral studies. Some of the new synthesized compounds were screened for antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacteria (Escherichia coli and Shigilla flexneri) and antifungal activity against Aspergillus flavus and Candida albicans. Compound 8 j was equipotent to chloramphenicol in inhibiting the growth of E. coli minimum inhibitory concentration (MIC 2.5 ?g/mL). Compound 8j may possibly be used as a lead compound for developing a new antibacterial agents. The antibacterial activity is expressed as the corresponding MIC (?g/mL) values. PMID:22651801
Kandile, Nadia G; Zaky, Howida T; Saleh, Yassmin G; Ahmed, Nashwa A
Potential applications of plant based derivatives as fat replacers, antioxidants and antimicrobials in fresh and processed meat products.
Growing concern about diet and health has led to development of healthier food products. In general consumer perception towards the intake of meat and meat products is unhealthy because it may increase the risk of diseases like cardiovascular diseases, obesity and cancer, because of its high fat content (especially saturated fat) and added synthetic antioxidants and antimicrobials. Addition of plant derivatives having antioxidant components including vitamins A, C and E, minerals, polyphenols, flavanoids and terpenoids in meat products may decrease the risk of several degenerative diseases. To change consumer attitudes towards meat consumption, the meat industry is undergoing major transformations by addition of nonmeat ingredients as animal fat replacers, natural antioxidants and antimicrobials, preferably derived from plant sources. PMID:24845336
Hygreeva, Desugari; Pandey, M C; Radhakrishna, K
Potential application of gaseous nitric oxide as a topical antimicrobial agent.
The presence of bacterial colonization in non-healing wounds and burn injuries interferes significantly with the normal process of healing. Recent evidence suggests that nitric oxide (NO) plays an important role in host defense against infection and regulates wound healing and angiogenesis. We investigated the potential application of a medical-grade gaseous form of NO (gNO) as a novel antibacterial agent in wound infection. Using a continuous horizontal-flow delivery system, the antibacterial activity of gNO was tested in vitro against a range of pathogens, including clinical isolates of Staphylococcus aureus, methicillin-resistant S. aureus, Escherichia coli, Group B Streptococcus, Pseudomonas aeruginosa, and Candida albicans. To probe the effect of topical application of gNO on the human skin, the proliferation and extracellular matrix gene expression of human dermal fibroblasts in culture were also analyzed by (3)H-thymidine incorporation assay and Northern blot techniques, respectively. Potent bacteriocidal activity was observed at 200 ppm gNO with an average of 4.1 +/- 1.1 h to completely stop bacterial growth. Interestingly, this dose of gNO did not show any cytotoxic effect in human dermal fibroblasts in culture exposed for up to 48 h. Analysis of gene transcription in fibroblasts revealed a significant increase in MMP-1 mRNA expression as early as 2 h post-exposure to gNO. Although to a lesser degree, a significant reduction in type I procollagen was also observed in the same fibroblasts. The results of this study suggest that exogenous gaseous NO has potent significant antibacterial properties that can be beneficial in reducing bacterial burden in infected wound in burn injuries or non-healing ulcers. PMID:16188471
Ghaffari, A; Miller, C C; McMullin, B; Ghahary, A
Phenolic characterization and antimicrobial activity of folk medicinal plant extracts for their applications in olive production.
Phytophthora spp is important in plant pathology due to the importance of the diseases it causes. In olive trees, severe damages are caused by the disease known as "dry branch" occasioned by Phytophthora nicotianae, P. citrophthora and P. palmivora. Much effort has been made to find efficient methods of control, with a low negative impact on environment. In this regard, treatment with plant extracts is a valid strategy. The aims of the present study are (i) to determine the polyphenol composition of extracts of Thymus vulgaris, Origanum vulgare, Matricaria recutita, and Larrea divaricata by CZE, (ii) correlate the analytical composition of these extracts with the inhibition on the mycelial growth, and (iii) determine the individual antimicrobial activity of the most active ingredients. A simple methodology was developed for the determination of catechin, naringenin, cinnamic acid, syringic acid, chlorogenic acid, apigenin, vanillic acid, luteolin, quercetin, and caffeic acid in plant extracts by CZE. The extraction of phenolic compounds in extract was performed by a miniaturized solid phase extraction using a home-made minicolumn packed with suitable filtering material (C18 , 50 mg). The optimized analyses conditions were: 30 mM boric acid buffer, pH 9.50; capillary, 57 cm full length, 50 cm effective length, 75 ?m id, hydrodynamic injection 30 mbar, 2 s; 25 kV; 25°C, detection by UV absorbance at 290 nm. Sample results suggest that phenolic composition seems to have a great influence on inhibition of pathogens. The highest inhibitions of mycelial growth were observed for cinnamic acid and naringenin. PMID:24668423
Boiteux, Joana; Vargas, Carolina Soto; Pizzuolo, Pablo; Lucero, Gabriela; Silva, María Fernanda
Antimicrobial, cytotoxicity and phytochemical screening of Jordanian plants used in traditional medicine.
Antimicrobial activity and cytotoxicity of fifty one extracts of different parts of 14 plants were studied. Ethanol, methanol, aqueous, butanol, and n-hexane extracts were tested against three gram negative, two gram positive bacteria, and two fungi. Cytotoxicity and phytochemical screening were determined using MTT and TLC assays, respectively. Of the fifty one extracts, twenty two showed activities against different microorganisms with MICs ranging from 62.5 to 1000 microg/mL. The highest activity (100% inhibition) was for a butanol extract of Rosa damascena receptacles against Salmonella typhimurium and Bacillus cereus (MIC of 62.5 and 250 microg/mL) respectively. Butanol extract of Narcissus tazetta aerial parts and aqueous extract of Rosa damascena receptacles were both active against Candida albicans (MIC of 125 microg/mL). Methicillin-resistant Staphylococcus aureus was inhibited by butanol, aqueous extracts of Rosa damascena receptacles and butanol extract of Inula viscosa flowers (MIC of 500, 500, and 250 microg/mL) respectively. Rosa damascena receptacles and Verbascum sinaiticum flowers ethanol extract showed lowest cytotoxicity against Vero cell line (IC50 of 454.11 and 367.11). Most toxic was the ethanol extract of Ononis hirta aerial parts (IC50 72.50 microg/mL). Flavonoids and terpenoids were present in all plants. Ononis hirta and Narcissus tazetta contained alkaloids. The results validate the use of these plants and report for the first time bioactivity of Rosa damascena receptacles and further justifies the use of such screening programs in the quest for new drugs. PMID:20336015
Talib, Wamidh H; Mahasneh, Adel M
Cumulative irritancy comparison of adapalene gel 0.1% versus other retinoid products when applied in combination with topical antimicrobial agents.
This randomized, investigator-blinded study evaluated the level of skin tolerance to adapalene gel 0.1%, tretinoin cream 0.025%, or tretinoin microsphere gel 0.1% when applied in combination with clindamycin phosphate lotion 1%, erythromycin gel 2%, benzoyl peroxide gel 5%, or erythromycin-benzoyl peroxide gel. A total of 37 subjects underwent daily application of the topical antimicrobial and retinoid products to sites on their upper back under protective patches for approximately 16 hours each day; Friday patches were left in place over the weekend. Testing continued daily for 3 weeks or until discontinuation caused by a severe adverse reaction to any of the test products or to the patch. Adapalene gel 0.1% demonstrated statistically significantly (P <.001) less irritation after repeated application under occlusive conditions than tretinoin cream 0.025% or tretinoin microsphere gel 0.1%. Moreover, the application of adapalene gel 0.1% under these conditions, concomitantly with various antimicrobial agents, was safe and well tolerated in this subject population. In view of its low irritation potential and its efficacy, adapalene gel 0.1%, in combination with antimicrobial agents should be considered for the treatment of acne vulgaris. PMID:12963899
Brand, Barbara; Gilbert, Richard; Baker, Michael D; Poncet, Michel; Greenspan, Alan; Georgeian, Kathleen; Soloff, Andrew-Marc
A (2)H solid-state NMR study of the effect of antimicrobial agents on intact Escherichia coli without mutating.
Solid-state nuclear magnetic resonance (NMR) is a useful tool to probe the organization and dynamics of phospholipids in bilayers. The interactions of molecules with membranes are usually studied with model systems; however, the complex composition of biological membranes motivates such investigations on intact cells. We have thus developed a protocol to deuterate membrane phospholipids in Escherichia coli without mutating to facilitate (2)H solid-state NMR studies on intact bacteria. By exploiting the natural lipid biosynthesis pathway and using perdeuterated palmitic acid, our results show that 76% deuteration of the phospholipid fatty acid chains was attained. To verify the responsiveness of these membrane-deuterated E. coli, the effect of known antimicrobial agents was studied. (2)H solid-state NMR spectra combined to spectral moment analysis support the insertion of the antibiotic polymyxin B lipid tail in the bacterial membrane. The use of membrane-deuterated bacteria was shown to be important in cases where antibiotic action of molecules relies on the interaction with lipopolysaccharides. This is the case of fullerenol nanoparticles which showed a different effect on intact cells when compared to dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol membranes. Our results also suggest that membrane rigidification could play a role in the biocide activity of the detergent cetyltrimethyammonium chloride. Finally, the deuterated E. coli were used to verify the potential antibacterial effect of a marennine-like pigment produced by marine microalgae. We were able to detect a different perturbation of the bacteria membranes by intra- and extracellular forms of the pigment, thus providing valuable information on their action mechanism and suggesting structural differences. PMID:22989726
Tardy-Laporte, Catherine; Arnold, Alexandre A; Genard, Bertrand; Gastineau, Romain; Morançais, Michčle; Mouget, Jean-Luc; Tremblay, Réjean; Marcotte, Isabelle
Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents
Background Development of an environmentally benign process for the synthesis of silver nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag+ ions using D. bulbifera tuber extract. Methods and results Phytochemical analysis revealed that D. bulbifera tuber extract is rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid. The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours. Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag+ ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (eryth-romycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa, and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli, providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles. Conclusion This is the first report on the synthesis of silver nanoparticles using D. bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents.
Ghosh, Sougata; Patil, Sumersing; Ahire, Mehul; Kitture, Rohini; Kale, Sangeeta; Pardesi, Karishma; Cameotra, Swaranjit S; Bellare, Jayesh; Dhavale, Dilip D; Jabgunde, Amit; Chopade, Balu A
Phytochemical screening and evaluation of Monechma ciliatum (black mahlab) seed extracts as antimicrobial agents
Objective: Tribes in Nubia Mountains regions of Sudan used Monechma ciliatum seeds for common cold and other chest allergic conditions as a traditional medicine. The aim of this paper is to validate this traditional practice scientifically. Materials and Methods: Monechma ciliatum seeds were screened for major phytochemical groups using standard methods. Different extracts were bioassayed in- vitro for their bioactivity to inhibit the growth of pathogenic bacteria and fungi. Results: Phytochemical screening results showed the presence of flavonoids, tannins, triterpens, and anthraquinones. Staphylococcus aureus was found to be sensitive to both water extract with zones of inhibition 22 – 26 mm at concentrations of 50 and 100mg/ml and ethanol extract 17 mm at concentration of 100 mg/ml. The growth of Klebsiella pneumoniae was inhibited by ethanol extract with zones of inhibition equal to 16, 26, and 33 mm at concentrations of 50, 100, and 150 mg/ml, respectively. Pseudomonas aeruginosa was insensitive to all extracts used. Similarly, all used fungi were found to be insensitive to extracts used. The minimum inhibitory concentrations of the extracts against microorganisms were ranged from 12.5 to 25 mg/ml. Conclusion: The findings of the current study support the traditional uses of the plant's seed in the therapy of respiratory tract infections caused by Staphylococcus aureus and Klebsiella pneumoniae.
Ahmed Oshi, Murtada; Mohmmed Abdelkarim, Abdelkarim
Antimicrobial and antioxidative activity of extracts and essential oils of Myrtus communis L.
Since synthetic antimicrobial agents and food additives can cause a number of adverse effects, there is a growing interest from consumers in ingredients from natural sources. Medicinal plants, such as Myrtus communis L. are a source of new compounds which can be used in both the food industry and for medical purposes, primarily as antimicrobial agents. In this review, the characteristics of myrtle essential oils and extracts are summarized, with particular attention to their chemical composition, biological activities and potential applications. PMID:24291016
Aleksic, Verica; Knezevic, Petar
Antimicrobial activity of diterpenoids from hairy roots of Salvia sclarea L.: Salvipisone as a potential anti-biofilm agent active against antibiotic resistant Staphylococci
The antimicrobial activities of crude dichloromethane fractions from acetone extracts of Agrobacterium rhizogenes transformed roots and roots of field-grown plants of Salvia sclarea as well as four pure abietane diterpenoids isolated from the hairy root cultures were determined. The growth of Gram-positive bacteria (Staphylococcus aureus, S. epidermidis, Enterococcus faecalis) but not Gram-negative ones (Escherichia coli, Pseudomonas aeruginosa) or pathogenic fungi
?. Ku?ma; M. Ró?alski; E. Walencka; B. Ró?alska; H. Wysoki?ska
Antimicrobial susceptibility pattern of bacterial isolates from wound infection and their sensitivity to alternative topical agents at Jimma University Specialized Hospital, South-West Ethiopia
Background Wound infection is one of the health problems that are caused and aggravated by the invasion of pathogenic organisms. Information on local pathogens and sensitivity to antimicrobial agents, and topical agents like acetic acid is crucial for successful treatment of wounds. Objectives To determine antimicrobial susceptibility pattern of bacterial isolates from wound infection and their sensitivity to alternative topical agents at Jimma University Specialized Hospital. Methods A cross sectional study was conducted among patients with wound infection visiting Jimma University Specialized Hospital, from May to September 2013. Wound swab was collected using sterile cotton swabs and processed for bacterial isolation and susceptibility testing to antimicrobial agents, acetic acid, hydrogen peroxide and dabkin solution following standard bacteriological techniques. Biochemical tests were done to identify the species of the organisms. Sensitivity testing was done using Kirby- Baur disk diffusion method. Minimum inhibitory and bactericidal concentration was done using tube dilution method. Results In this study 145 bacterial isolates were recovered from 150 specimens showing an isolation rate of 87.3%. The predominant bacteria isolated from the infected wounds were Staphylococcus aureus 47 (32.4%) followed by Escherichia coli 29 (20%), Proteus species 23 (16%), Coagulase negative Staphylococci 21 (14.5%), Klebsiella pneumoniae 14 (10%) and Pseudomonas aeruginosa 11 (8%). All isolates showed high frequency of resistance to ampicillin, penicillin, cephalothin and tetracycline. The overall multiple drug resistance patterns were found to be 85%. Acetic acid (0.5%), Dabkin solution (1%) and 3% hydrogen peroxide were bactericidal to all isolated bacteria and lethal effect observed when applied for 10 minutes. Conclusions On in vitro sensitivity testing, ampicillin, penicillin, cephalothin and tetracycline were the least effective. Gentamicin, norfloxacin, ciprofloxacin, vancomycin and amikacin were the most effective antibiotics. Acetic acid (0.5%), dabkin solution (1%) and H2O2 (3%) were bactericidal to all isolates.
Gold complexes as antimicrobial agents: an overview of different biological activities in relation to the oxidation state of the gold ion and the ligand structure.
Interest in antimicrobial gold complexes originated from the work of Robert Koch at the end of 19th century, who demonstrated that potassium dicyanidoaurate(I), K[Au(CN)2], showed activity against Mycobacterium tuberculosis, a causative agent of tuberculosis. Subsequently, a large number of gold(I) and gold(III) complexes have been evaluated as possible antimicrobial agents against a broad spectrum of bacteria, fungi and parasites. The first part of the present review article summarizes the results achieved in the field of antibacterial and antifungal activity of gold(I) and gold(III) complexes. The represented gold(I) complexes have been divided into three distinct classes based on the type of coordinated ligand: (i) complexes with phosphine-type ligands, (ii) complexes with N-heterocyclic carbene ligands and (iii) various other gold(I) complexes, while the results related to the antibacterial and antifungal gold(III) complexes have been mainly focused on the organometallic-type of complexes. The second section of this article represents findings obtained from the evaluation of antimalarial activity of gold complexes against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum parasite. Antimalarial gold(I) and gold(III) complexes have been divided into the following classes, based on the nature of the coordinated ligand: (i) complexes with chloroquine and its derivatives, (ii) complexes with N-heterocyclic carbene ligands, (iii) complexes containing functionalised alkynes and (iv) thiosemicarbazonato ligands, as well as (v) other gold(I) and gold(III) complexes. In the last section of the review, gold(I) and gold(III) complexes have been reported to be potential agents against parasites that cause amoebiasis, leishmaniasis and trypanosomiasis. A systematic summary of these results could contribute to the future design of new gold(I) and gold(III) complexes as potential antimicrobial agents. PMID:24598838
Gliši?, Biljana ?; Djuran, Miloš I
Transgenic Brassica juncea plants expressing MsrA1, a synthetic cationic antimicrobial peptide, exhibit resistance to fungal phytopathogens.
Cationic antimicrobial peptides (CAPs) have shown potential against broad spectrum of phytopathogens. Synthetic versions with desirable properties have been modeled on these natural peptides. MsrA1 is a synthetic chimera of cecropin A and melittin CAPs with antimicrobial properties. We generated transgenic Brassica juncea plants expressing the msrA1 gene aimed at conferring fungal resistance. Five independent transgenic lines were evaluated for resistance to Alternaria brassicae and Sclerotinia sclerotiorum, two of the most devastating pathogens of B. juncea crops. In vitro assays showed inhibition by MsrA1 of Alternaria hyphae growth by 44-62 %. As assessed by the number and size of lesions and time taken for complete leaf necrosis, the Alternaria infection was delayed and restricted in the transgenic plants with the protection varying from 69 to 85 % in different transgenic lines. In case of S. sclerotiorum infection, the lesions were more severe and spread profusely in untransformed control compared with transgenic plants. The sclerotia formed in the stem of untransformed control plants were significantly more in number and larger in size than those present in the transgenic plants where disease protection of 56-71.5 % was obtained. We discuss the potential of engineering broad spectrum biotic stress tolerance by transgenic expression of CAPs in crop plants. PMID:24452332
Rustagi, Anjana; Kumar, Deepak; Shekhar, Shashi; Yusuf, Mohd Aslam; Misra, Santosh; Sarin, Neera Bhalla
The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development.
Chavasco, Juliana Moscardini; Prado E Feliphe, Barbara Helena Muniz; Cerdeira, Claudio Daniel; Leandro, Fabricio Damasceno; Coelho, Luiz Felipe Leomil; da Silva, Jeferson Junior; Chavasco, Jorge Kleber; Dias, Amanda Latercia Tranches
Evaluation of antimicrobial and cytotoxic activities of plant extracts from southern Minas Gerais cerrado.
The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development. PMID:24553603
Chavasco, Juliana Moscardini; Prado E Feliphe, Bárbara Helena Muniz; Cerdeira, Claudio Daniel; Leandro, Fabrício Damasceno; Coelho, Luiz Felipe Leomil; Silva, Jéferson Junior da; Chavasco, Jorge Kleber; Dias, Amanda Latercia Tranches
Chemokines are best known for their classic leukocyte chemotactic activity, which is critical for directing the immune response to sites of infection and injury. However, recent studies have suggested that at least some chemokines may also interfere with infectious agents directly. Antimicrobial chemokines tend to contain amphipathic alpha helical secondary structure, and broad-spectrum activity against both Gram-positive and Gram negative bacteria, as well as fungi. Conversely, several bacteria have been identified that possess mechanisms for specifically blocking the antimicrobial activities of chemokines. Although the precise mechanisms by which chemokines and microbes disarm one another in vitro remain unknown, there is now emerging evidence in vivo that such interactions may be biologically significant. More research will be needed to determine whether chemokines with direct antimicrobial activity may be translated into a novel class of antibiotics.
Yung, Sunny C.; Murphy, Philip M.
Rapid inactivation of Salmonella Enteritidis on shell eggs by plant-derived antimicrobials.
Salmonella Enteritidis is a common foodborne pathogen transmitted to humans largely by consumption of contaminated eggs. The external surface of eggs becomes contaminated with Salmonella Enteritidis from various sources on farms, the main sources being hens' droppings and contaminated litter. Therefore, effective egg surface disinfection is critical to reduce pathogens on eggs and potentially control egg-borne disease outbreaks. This study investigated the efficacy of GRAS (generally recognized as safe) status, plant-derived antimicrobials (PDA), namely trans-cinnamaldehyde (TC), carvacrol (CR), and eugenol (EUG), as an antimicrobial wash for rapidly killing Salmonella Enteritidis on shell eggs in the presence or absence of chicken droppings. White-shelled eggs inoculated with a 5-strain mixture of nalidixic acid (NA) resistant Salmonella Enteritidis (8.0 log cfu/mL) were washed in sterile deionized water containing each PDA (0.0, 0.25, 0.5, or 0.75%) or chlorine (200 mg/kg) at 32 or 42°C for 30 s, 3 min, or 5 min. Approximately 6.0 log cfu/mL of Salmonella Enteritidis was recovered from inoculated and unwashed eggs. The wash water control and chlorine control decreased Salmonella Enteritidis on eggs by only 2.0 log cfu/mL even after washing for 5 min. The PDA were highly effective in killing Salmonella Enteritidis on eggs compared with controls (P < 0.05). All treatments containing CR and EUG reduced Salmonella Enteritidis to undetectable levels as rapidly as within 30 s of washing, whereas TC (0.75%) completely inactivated Salmonella Enteritidis on eggs washed at 42°C for 30 s (P < 0.05). No Salmonella Enteritidis was detected in any PDA or chlorine wash solution; however, substantial pathogen populations (~4.0 log cfu/mL) survived in the antibacterial-free control wash water (P < 0.05). The CR and EUG were also able to eliminate Salmonella Enteritidis on eggs to undetectable levels in the presence of 3% chicken droppings at 32°C (P < 0.05). This study demonstrates that PDA could effectively be used as a wash treatment to reduce Salmonella Enteritidis on shell eggs. Sensory and quality studies of PDA-washed eggs need to be conducted before recommending their use. PMID:24235233
Upadhyaya, Indu; Upadhyay, Abhinav; Kollanoor-Johny, Anup; Baskaran, Sangeetha Ananda; Mooyottu, Shankumar; Darre, Michael J; Venkitanarayanan, Kumar
Plant-Derived Anticancer Agents Used in Western and Oriental Medicine
\\u000a Cancer chemotherapeutic agents derived from higher plants are used in Western medicine. Secondary metabolites from plants\\u000a are used in oriental medicine are utilized in anticancer therapy. Immunomodulatory small organic molecules from plant species\\u000a are employed in Chinese traditional medicine are renewed.
Ah-Reum Han; Ye Deng; Yulin Ren; Li Pan; A. Douglas Kinghorn
Potency of anidulafungin compared to nine other antifungal agents tested against Candida spp., Cryptococcus spp., and Aspergillus spp.: results from the global SENTRY Antimicrobial Surveillance Program (2008).
The SENTRY Antimicrobial Surveillance Program regularly monitors global susceptibility rates for a spectrum of both novel and established antifungal agents. Anidulafungin and the other echinocandins displayed sustained, excellent activity against Candida spp. and Aspergillus fumigatus, with >or=98% of MIC results at
Messer, Shawn A; Jones, Ronald N; Moet, Gary J; Kirby, Jeffrey T; Castanheira, Mariana
Susceptibility to Alternative Oral Antimicrobial Agents in Relation to Sequence Type ST131 Status and Coresistance Phenotype among Recent Escherichia coli Isolates from U.S. Veterans
The rising prevalence of resistance to first-line antimicrobial agents in Escherichia coli, which has paralleled the emergence of E. coli sequence type ST131, has created a need for alternative oral options for use in treating outpatients with infections such as cystitis and chronic prostatitis. Accordingly, we determined susceptibility to six alternative oral agents (azithromycin, chloramphenicol, doxycycline, fosfomycin, minocycline, and rifampin) by Etest or disk diffusion for 120 recently obtained E. coli clinical isolates from Veterans Affairs Medical Centers across the United States. Isolates were randomly selected in three subgroups of 40 isolates each based on coresistance to fluoroquinolones with and without extended-spectrum cephalosporins (ESCs). Results were stratified according to trimethoprim-sulfamethoxazole (TMP-SMZ) phenotype. Overall, the prevalence of susceptible (or susceptible plus intermediate) isolates varied by agent, with rifampin being lowest (0%), fosfomycin highest (98 to 99%), and others in the mid-range (37 to 88%). Substantial proportions of isolates (15 to 27%) yielded intermediate results for azithromycin, chloramphenicol, doxycycline, and minocycline. Among isolates resistant (versus susceptible) to fluoroquinolones with or without ESCs, susceptibility to the above four agents declined significantly among non-ST131 isolates but not ST131 isolates. In contrast, in the presence of resistance to TMP-SMZ, susceptibility to azithromycin, doxycycline, and minocycline was significantly reduced among both ST131 and non-ST131 isolates. These findings identify potential alternative oral agents for use with E. coli isolates resistant to fluoroquinolones, ESCs, and/or TMP-SMZ and suggest that determination of ST131 status could help guide initial antimicrobial selection, pending susceptibility results.
Drawz, Sarah M.; Porter, Stephen; Kuskowski, Michael A.
In vitro activities of 16 antimicrobial agents against clinical isolates of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in two regional hospitals in Taiwan
Background and Purpose: Infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EC and ESBL-KP) have become an important clinical problem. Local knowledge of antimicrobial susceptibilities of these organisms is important for implementation of effective hospital anti-infective policies. Methods: We analyzed the activities of various antimicrobial agents against recent isolates of ESBL-EC and ESBL- KP from 2 regional
Chun-Hsing Liao; Wang-Huei Sheng; Jann-Tay Wang; Hsin-Yun Sun; Hua-Kung Wang; Po-Ren Hsueh; Yee-Chun Chen; Shan-Chwen Chang
In Vitro Model of Colonization Resistance by the Enteric Microbiota: Effects of Antimicrobial Agents Used in Food-Producing Animals?
A bioassay was developed to measure the minimum concentration of an antimicrobial drug that disrupts the colonization resistance mediated by model human intestinal microbiota against Salmonella invasion of Caco-2 intestinal cells. The bioassay was used to measure the minimum disruptive concentrations (MDCs) of drugs used in animal agriculture. The MDCs varied from 0.125 ?g/ml for some broad-spectrum antimicrobial drugs (e.g., streptomycin) to 16 ?g/ml for drugs with limited spectra of antimicrobial activity (e.g., lincomycin). The acceptable daily intake (ADI) residue concentration calculated on the basis of the MDCs were higher for erythromycin, lincomycin, and tylosin than the ADI residue concentrations calculated on the basis of the MICs. The MDC-based ADI values for apramycin, bacitracin, neomycin, novobiocin, penicillin G, streptomycin, tetracycline, and vancomycin were lower than the reported MIC-based ADI values. The effects of antimicrobial drugs at their MDCs on the bacterial composition of the microbiota were observed by denaturing gradient gel electrophoresis of 16S rRNA sequences amplified by PCR. Changes in the population composition of the model colonization resistance microbiota occurred simultaneously with reduced colonization resistance. The results of this study suggest that direct assessment of the effects of antimicrobial drugs on colonization resistance in an in vitro model can be useful in determining ADI values.
Wagner, R. Doug; Johnson, Shemedia J.; Cerniglia, Carl E.
The mode of action of the plant antimicrobial peptide MiAMP1 differs from that of its structural homologue, the yeast killer toxin WmKT
The plant antimicrobial peptide MiAMP1 from Macadamia integrifolia and the yeast killer toxin peptide WmKT from Williopsis mrakii are structural homologues. Comparative studies of yeast mutants were performed to test their sensitivity to these two antimicrobial peptides. No differences in susceptibility to MiAMP1 were detected between wild-type and several WmKT-resistant mutant yeast strains. A yeast mutant MT1, resistant to MiAMP1
Camilla Stephens; Kemal Kazan; Ken C. Goulter; Donald J. Maclean; John M. Manners
Design and synthesis of biquinolone-isoniazid hybrids as a new class of antitubercular and antimicrobial agents.
Twenty four biquinolone-isoniazid hybrids were designed based on molecular hybridization technique and synthesized via multicomponent cyclocondensation (MCC) approach. All the newly synthesized compounds were screened for their antimicrobial and antitubercular activities. The brine shrimp bioassay was carried out to study the cytotoxicity of the synthesized compounds. Hybrids 7f (MIC = 25 ?g/mL); 7a, 7e and 7m (MIC = 50 ?g/mL); 7g, 7h and 7k (MIC = 62.5 ?g/mL) exhibited excellent antimicrobial activity as compared with standard drugs. Hybrids 7l and 7j displayed 99% inhibition against Mycobacterium tuberculosis bacteria with better LC50 values 35.39 and 34.59 ?g/mL, respectively. These results indicate that the synthesized compounds can act as leads for the development of newer antimicrobial and antitubercular compounds. PMID:23747804
Jardosh, Hardik H; Patel, Manish P
Effect of 1-(1-naphthylmethyl)-piperazine on antimicrobial agent susceptibility in multidrug-resistant isogenic and veterinary Escherichia coli field strains.
The objective of this study was to evaluate the interaction of the efflux pump inhibitor 1-(1-naphthylmethyl)-piperazine (NMP) when combined with different families of antimicrobial agents against isogenic strains and multidrug-resistant (MDR) Escherichia coli field strains isolated from animals. Laboratory isogenic strains of E. coli with different levels of expression of efflux pumps were used as quality controls. Ten MDR E. coli strains were collected from healthy animals in a cross-sectional study in four commercial dairy farms. The MICs of florfenicol, ciprofloxacin, tetracycline and ampicillin were determined by a serial microdilution method in Luria-Bertani broth in the presence or absence of NMP. NMP used with ampicillin exerted no effect on the isogenic or field strains. In most of the field MDRE. coli strains and in an acrAB-overexpressing (AG112) isogenic strain, the MICs of florfenicol, ciprofloxacin and tetracycline decreased at least fourfold when the antimicrobial was combined with the highest NMP concentrations. In the wild-type strain (AG100), there were no decreases of more than twice the MIC, whilst in strain AG100A, an efflux pump-deficient strain, the MIC did not change, regardless of the concentration of NMP used with these three antimicrobials. Thus, ampicillin was not affected by the efflux pump mechanism, whereas ciprofloxacin, tetracycline and florfenicol were shown to be substrates of efflux pumps, with a consequent significant reduction in MICs. Resistance could not be completely reversed in the E. coli field strains by NMP, probably because other resistance mechanisms were also present. However, in strain AG112, the MIC results demonstrated that NMP expressed an important synergistic activity with florfenicol. The reduction in florfenicol MIC value was sufficient to reverse antimicrobial resistance completely for AG112. PMID:22345599
Marchetti, M L; Errecalde, J; Mestorino, N
Studies of the in vitro anticancer, antimicrobial and antioxidant potentials of selected Yemeni medicinal plants from the island Soqotra
Background Recent years have witnessed that there is a revival of interest in drug discovery from medicinal plants for the maintenance of health in all parts of the world. The aim of this work was to investigate 26 plants belonging to 17 families collected from a unique place in Yemen (Soqotra Island) for their in vitro anticancer, antimicrobial and antioxidant activities. Methods The 26 plants were extracted with methanol and hot water to yield 52 extracts. Evaluation for in vitro anticancer activity was done against three human cancer cell lines (A-427, 5637 and MCF-7) by using an established microtiter plate assay based on cellular staining with crystal violet. Antimicrobial activity was tested against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains by using an agar diffusion method and the determination of MIC against three Gram-positive bacteria with the broth micro-dilution assay. Antioxidant activity was investigated by measuring the scavenging activity of the DPPH radical. Moreover, a phytochemical screening of the methanolic extracts was done. Results Notable cancer cell growth inhibition was observed for extracts from Ballochia atro-virgata, Eureiandra balfourii and Hypoestes pubescens, with IC50 values ranging between 0.8 and 8.2 ?g/ml. The methanol extracts of Acanthospermum hispidum, Boswellia dioscorides, Boswellia socotrana, Commiphora ornifolia and Euphorbia socotrana also showed noticeable antiproliferative potency with IC50 values < 50 ?g/ml. The greatest antimicrobial activity was exhibited by extracts from Acacia pennivenia, Boswellia dioscorides, Boswellia socotrana, Commiphora ornifolia, Euclea divinorum, Euphorbia socotrana, Leucas samhaensis, Leucas virgata, Rhus thyrsiflora, and Teucrium sokotranum with inhibition zones > 15 mm and MIC values ? 250 ?g/ml. In addition, the methanolic extracts of Acacia pennivenia, Boswellia dioscorides, Boswellia socotrana and Commiphora ornifolia showed good antioxidant potential at low concentrations (more than 80% at 50 ?g/ml). Conclusion Our results show once again that medicinal plants can be promising sources of natural products with potential anticancer, antimicrobial and antioxidative activity. The results will guide the selection of some plant species for further pharmacological and phytochemical investigations.
Efficacy of the novel topical antimicrobial agent PXL150 in a mouse model of surgical site infections.
Antimicrobial peptides have recently emerged as a promising new group to be evaluated in the therapeutic intervention of infectious diseases. This study evaluated the anti-infectious effect of the short, synthetic, broad-spectrum antimicrobial peptide PXL150 in a mouse model of staphylococcal surgical site infections. We found that administration of PXL150, formulated in an aqueous solution or in a hydroxypropyl cellulose gel, significantly reduced the bacterial counts in the wound compared with placebo treatment, warranting further investigations of the potential of this peptide as a novel local treatment of microbial infections. PMID:24590479
Hĺkansson, Joakim; Björn, Camilla; Lindgren, Kerstin; Sjöström, Emma; Sjöstrand, Veronika; Mahlapuu, Margit
Evaluation of minimum inhibitory and minimum bactericidal concentration of nano-silver base inorganic anti-microbial agent (Novaron®) against streptococcus mutans
Objective: We attempted to find the possibility of determining the minimum inhibitory concentration and minimum bactericidal concentration needed for nano-silver base inorganic anti-microbial agent (Novaron® AG 300, AG 1100) against Streptococcus mutans in vitro using broth dilution assay. Materials and Methods: An ampoule of freeze-dried S. mutans NCTC reference strain was revived, and the colony-forming units (CFU) were calculated. The MIC and MBC was determined by broth dilution assay using different concentrations of Novaron® AG 300 and Novaron® AG 1100 against 1 × 105 CFU/ml of S. mutans. Results: The MIC and MBC of Novaron® AG 300 and Novaron® AG 1100 against S. mutans were found to be 40 ?g/ml. Conclusions: Novaron® has anti-bacterial effect against S. mutans. Further studies are needed to explore the applicability of these silver-supported anti- microbial agents in clinical dentistry.
Holla, Goda; Yeluri, Ramakrishna; Munshi, Autar Krishen
Repositioning Antimicrobial Agent Pentamidine as a Disruptor of the Lateral Interactions of Transmembrane Domain 5 of EBV Latent Membrane Protein 1
The lateral transmembrane protein-protein interactions (PPI) have been regarded as "undruggable" despite their importance in many essential biological processes. The homo-trimerization of transmembrane domain 5 (TMD-5) of latent membrane protein 1 (LMP-1) is critical for the constitutive oncogenic activation of the Epstein-Barr virus (EBV). Herein we repurpose the antimicrobial agent pentamidine as a regulator of LMP-1 TMD-5 lateral interactions. The results of ToxR assay, tryptophan fluorescence assay, courmarin fluorescence dequenching assay, and Bis-Tris sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) consistently show pentamidine disrupts LMP-1 TMD-5 lateral interactions. Furthermore, pentamidine inhibits LMP-1 signaling, inducing cellular apoptosis and suppressing cell proliferation in the EBV infected B cells. In contrast, EBV negative cells are less susceptible to pentamidine. This study provides a novel non-peptide small molecule agent for regulating LMP-1 TMD-5 lateral interactions.
Wang, Xiaohui; Fiorini, Zeno; Smith, Christina; Zhang, Yingning; Li, Jing; Watkins, Linda R.; Yin, Hang
Development of periodontal disease in a single flock of sheep: clinical signs, morphology of subgingival plaque and influence of antimicrobial agents.
The clinical development of broken mouth over a single reproductive year and the effect of two broad spectrum antibacterial agents upon it was followed in 72 Scottish Blackface ewes aged between two and three years. Using a number of dental health indices especially developed for the purpose, the amount of gingivitis, tooth movement, gum recession and pocketing were quantified and graphed for both the whole population and each group in the drug trial. All clinical features except movement fluctuated significantly with time, the fluctuations often being associated with nutritional or other environmental factors. Despite the extended use of large doses of two antimicrobial agents no significant reduction in the amount of clinical gingivitis or pocketing was evident. PMID:3212280
Spence, J A; Aitchison, G U; Fraser, J
Potential Antiosteoporotic Agents from Plants: A Comprehensive Review
Osteoporosis is a major health hazard and is a disease of old age; it is a silent epidemic affecting more than 200 million people worldwide in recent years. Based on a large number of chemical and pharmacological research many plants and their compounds have been shown to possess antiosteoporosis activity. This paper reviews the medicinal plants displaying antiosteoporosis properties including their origin, active constituents, and pharmacological data. The plants reported here are the ones which are commonly used in traditional medical systems and have demonstrated clinical effectiveness against osteoporosis. Although many plants have the potential to prevent and treat osteoporosis, so far, only a fraction of these plants have been thoroughly investigated for their physiological and pharmacological properties including their mechanism of action. An attempt should be made to highlight plant species with possible antiosteoporosis properties and they should be investigated further to help with future drug development for treating this disease.
Jia, Min; Nie, Yan; Cao, Da-Peng; Xue, Yun-Yun; Wang, Jie-Si; Zhao, Lu; Rahman, Khalid; Zhang, Qiao-Yan; Qin, Lu-Ping
Antimicrobial activity and phytochemical studies of some medicinal plants from Ghana Actividad antimicrobiana y estudios fitoquímicos de algunas plantas medicinales de Ghana
The methanol and petroleum ether extracts of the leaf and stem bark of Nauclea latifolia, Bridelia atroviridis and Zanthoxylum gilletii showed antimicrobial activity against the test organisms. The methanol extracts of the plants exhibited higher activity than the pet ether extract against the test organisms. The activity of the extracts may support some of the folkloric uses of these plants
In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments
The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments. Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal.
Yoldas, Oguz; Yilmaz, Sehnaz; Akcimen, Beril; Seydaoglu, Gulsah; Kipalev, Arzu; Koksal, Fatih
Antimicrobial activity of plant essential oils using food model media: efficacy, synergistic potential and interactions with food components.
The aim of this study was to optimise the antimicrobial efficacy of plant essential oils (EOs) for control of Listeria spp. and spoilage bacteria using food model media based on lettuce, meat and milk. The EOs evaluated were lemon balm, marjoram, oregano and thyme and their minimum inhibitory concentrations (MIC) were determined against Enterobacter spp., Listeria spp., Lactobacillus spp., and Pseudomonas spp. using the agar dilution method and/or the absorbance based microplate assay. MICs were significantly lower in lettuce and beef media than in TSB. Listeria strains were more sensitive than spoilage bacteria, and oregano and thyme were the most active EOs. EO combinations were investigated using the checkerboard method and Oregano combined with thyme had additive effects against spoilage organisms. Combining lemon balm with thyme yielded additive activity against Listeria strains. The effect of simple sugars and pH on antimicrobial efficacy of oregano and thyme was assessed in a beef extract and tomato serum model media. EOs retained greater efficacy at pH 5 and 2.32% sugar, but sugar concentrations above 5% did not negatively impact EO efficacy. In addition to proven antimicrobial efficacy, careful selection and investigation of EOs appropriate to the sensory profile of foods and composition of the food system is required. This work shows that EOs might be more effective against food-borne pathogens and spoilage bacteria when applied to foods containing a high protein level at acidic pH, as well as moderate levels of simple sugars. PMID:19171255
Gutierrez, J; Barry-Ryan, C; Bourke, P
TiO2 nanotube arrays deposited on Ti substrate by anodic oxidation and their potential as a long-term drug delivery system for antimicrobial agents
NASA Astrophysics Data System (ADS)
Nanotube arrays on medical titanium surfaces were fabricated by two different anodization methods and their potential for storage and release of antimicrobial substances was evaluated. The treatment of the Ti surfaces in fluoride containing electrolytes on water as well as on polyethylene glycol basis led to the formation of TiO2 nanotubes with up to 6.54 ?m length and average diameters of up to 160 nm. Drug release experiments with the model antibiotic vancomycin and with antibacterial silver ions showed that the increased surface area of the anodized samples enabled them to be loaded with up to 450% more active agent than the untreated Ti surfaces. Significant surface-dependent differences in the release kinetics of vancomycin were observed. In comparison to surfaces anodized in an aqueous electrolyte, the release of the antibiotic from surfaces anodized in an electrolyte based on ethylene glycol was significantly retarded, with a release of noticeable amounts over a period of more than 300 days. Loading of nanotube surfaces fabricated in aqueous electrolyte with silver ions revealed increased amounts of adsorbed silver by up to 230%, while the release kinetics showed significant differences in comparison to untreated Ti. It was concluded that nanotube arrays on favored medical implant materials have a high potential for loading with antimicrobial agents and also provide the possibility of tailored release kinetics by variation of anodization parameters.
Moseke, Claus; Hage, Felix; Vorndran, Elke; Gbureck, Uwe
Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.
The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species. PMID:21462837
Lixandru, Brîndu?a-Elena; Dr?cea, Nicoleta Olgu?a; Dragomirescu, Cristiana Cerasella; Dr?gulescu, Elena Carmina; Coldea, Ileana Lumini?a; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codi??, Irina
Cathelicidin-BF, a Snake Cathelicidin-Derived Antimicrobial Peptide, Could Be an Excellent Therapeutic Agent for Acne Vulgaris
Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O2.? production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O2.? production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris.
Chen, Lingling; Guang, Huijuan; Li, Zheng; Yang, Hailong; Li, Jianxu; You, Dewen; Yu, Haining; Lai, Ren
Cathelicidin-BF, a snake cathelicidin-derived antimicrobial peptide, could be an excellent therapeutic agent for acne vulgaris.
Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O2.- production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O2.- production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris. PMID:21789223
Wang, Yipeng; Zhang, Zhiye; Chen, Lingling; Guang, Huijuan; Li, Zheng; Yang, Hailong; Li, Jianxu; You, Dewen; Yu, Haining; Lai, Ren
Silver nanoparticles as antimicrobial agent: a case study on E. coli as a model for Gram-negative bacteria
The antimicrobial activity of silver nanoparticles against E. coli was investigated as a model for Gram-negative bacteria. Bacteriological tests were performed in Luria–Bertani (LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of nanosized silver particles. These particles were shown to be an effective bactericide. Scanning and transmission electron microscopy (SEM and TEM) were used
Ivan Sondi; Branka Salopek-Sondi
The report gives results of a study undertaken as a preliminary program to provide data on the environmental effects of a chemical flyash conditioning agent (Apollo Chemicals conditioner LPA 402A). Both the emissions due to the chemical and its effect on electrostatic precipitato...
Sustainable bioproduction of phytochemicals by plant in vitro cultures: anticancer agents
Due to their complex structure with several chiral centres important anticancer agents are still extracted from plants and not synthesized chemically on a commercial scale. Sustainable biopro- duction of the compounds of interest may be achieved by plant in vitro cultures. Undifferen- tiated callus and suspension cultures, which can be cultivated in large bioreactors easily, very often fail to accumulate
Michael Wink; A. Wilhelm Alfermann; Rochus Franke; Bernhard Wetterauer; Melanie Distl; Oliver Krohn; Elisabeth Fuss; Hermann Garden; Abdolali Mohagheghzadeh; Eckart Wildi; Peter Ripplinger
Antimicrobial properties of some West African medicinal plants iv. Antimicrobial activity of xylopic acid and other constituente of the fruits of Xylopia aethiopica (Annonaceae).
Xylopic acid and four other isolates from the fresh ripe fruits of Xylopia aethiopica a common ingredient in several Ghanaian folklore medicines and foods, have been examined for antimicrobial activity against five micro-organisms, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Xylopic acid and two other diterpene isolates were found to have antimicrobial properties. PMID:600023
Boakye-Yiadom, K; Fiagbe, N I; Ayim, J S
Multicenter Study in Taiwan of the In Vitro Activities of Nemonoxacin, Tigecycline, Doripenem, and Other Antimicrobial Agents against Clinical Isolates of Various Nocardia Species?
The aim of this study was to assess the in vitro activities of nemonoxacin (a novel nonfluorinated quinolone), doripenem, tigecycline, and 16 other antimicrobial agents against Nocardia species. The MICs of the 19 agents against 151 clinical isolates of Nocardia species were determined by the broth microdilution method. The isolates were identified to the species level using 16S rRNA gene sequencing analysis. The results showed that N. brasiliensis (n = 60; 40%) was the most common species, followed by N. cyriacigeorgica (n = 24; 16%), N. farcinica (n = 12; 8%), N. beijingensis (n = 9), N. otitidiscaviarum (n = 8), N. nova (n = 8), N. asiatica (n = 7), N. puris (n = 6), N. flavorosea (n = 5), N. abscessus (n = 3), N. carnea (2), and one each of N. alba, N. asteroides complex, N. rhamnosiphila, N. elegans, N. jinanensis, N. takedensis, and N. transvalensis. The MIC90s of the tested quinolones against the N. brasiliensis isolates were in the order nemonoxacin = gemifloxacin < moxifloxacin < levofloxacin = ciprofloxacin, and the MIC90s of the tested carbapenems were in the order doripenem = meropenem < ertapenem < imipenem. Tigecycline had a lower MIC90 (1 ?g/ml) than linezolid (8 ?g/ml). The MIC90s of the tested quinolones against N. cyriacigeorgica isolates were in the order nemonoxacin < gemifloxacin < moxifloxacin < levofloxacin < ciprofloxacin, and the MIC90s of the tested carbapenems were in the order imipenem < doripenem = meropenem < ertapenem. Nemonoxacin had the lowest MIC90 values among the tested quinolones against the other 17 Nocardia isolates. Among the four tested carbapenems, imipenem had the lowest MIC90s. All of the clinical isolates of N. beijingensis, N. otitidiscaviarum, N. nova, and N. puris and more than half of the N. brasiliensis and N. cyriacigeorgica isolates were resistant to at least one antimicrobial agent. The results of this in vitro study suggest that nemonoxacin, linezolid, and tigecycline are promising treatment options for nocardiosis. Further investigation of their clinical role is warranted.
Lai, Chih-Cheng; Liu, Wei-Lun; Ko, Wen-Chien; Chen, Yen-Hsu; Tan, Hon-Ren; Huang, Yu-Tsung; Hsueh, Po-Ren
Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants
We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus
N. C. C. Silva; L. Barbosa; L. N. Seito; A. Fernandes Junior
Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants
We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus
N. C. C. Silva; L. Barbosa; L. N. Seito; A. Fernandes Junior
Induction of Defense Responses in Cucumber Plants (Cucumis sativus L.) by the Biocontrol Agent Trichoderma harzianum
The potential of the biocontrol agent Trichoderma harzianum T-203 to trigger plant defense responses was investigated by inoculating roots of cucumber seedlings with Trichoderma in an aseptic, hydroponic system. Trichoderma-treated plants were more developed than nontreated plants throughout the experiment. Electron microscopy of ultrathin sections from Trichoderma-treated roots revealed penetration of Trichoderma into the roots, restricted mainly to the epidermis
Ecological and mechanistic insights into the direct and indirect antimicrobial properties of Bacillus subtilis lipopeptides on plant pathogens.
Members of the genus Bacillus produce a wide variety of antimicrobial compounds. Cyclic lipopeptides (CLP) produced by Bacillus subtilis strains have been shown to protect host plants from a numbers of pathogens. The representative families of these CLP (surfactins, fengycins, and iturins) share a polypeptide ring linked to a lipid tail of varying length. CLP provide plant protection through a variety of unique mechanisms. Members of the surfactin and fengycin families elicit induced systemic resistance in certain host plants, and they also function by directly affecting the biological membranes of bacterial and fungal pathogens, mainly resulting in membrane pore formation. Specific pore forming mechanisms differ between CLP families, causing differential activities. CLP also may aid in enhanced B. subtilis colonization of the plant environment in addition to potentially preventing the adhesion of competitive microorganisms. Several recent studies have highlighted the control of plant pathogens by CLP-producing B. subtilis strains. Strong ecological advantages through multifaceted activities of CLP provide these strains with immense promise in controlling pathogens in a variety of plant ecosystems. PMID:23888387
Falardeau, J; Wise, C; Novitsky, L; Avis, T J
The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill "superbugs" emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs), a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes) and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics).
Bahar, Ali Adem; Ren, Dacheng
The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill "superbugs" emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs), a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes) and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics). PMID:24287494
Bahar, Ali Adem; Ren, Dacheng
Danish Integrated Antimicrobial Resistance Monitoring and Research Program
Resistance to antimicrobial agents is an emerging problem worldwide. Awareness of the undesirable consequences of its widespread occurrence has led to the initiation of antimicrobial agent resistance monitoring programs in several countries. In 1995, Denmark was the first country to establish a systematic and continuous monitoring program of antimicrobial drug consumption and antimicrobial agent resistance in animals, food, and humans, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program (DANMAP). Monitoring of antimicrobial drug resistance and a range of research activities related to DANMAP have contributed to restrictions or bans of use of several antimicrobial agents in food animals in Denmark and other European Union countries.
Heuer, Ole E.; Emborg, Hanne-Dorthe; Bagger-Skj?t, Line; Jensen, Vibeke F.; Rogues, Anne-Marie; Skov, Robert L.; Agers?, Yvonne; Brandt, Christian T.; Seyfarth, Anne Mette; Muller, Arno; Hovgaard, Karin; Ajufo, Justin; Bager, Flemming; Aarestrup, Frank M.; Frimodt-M?ller, Niels; Wegener, Henrik C.; Monnet, Dominique L.
In vitro antibacterial activity of medicinal plant extracts against Escherichia coli strains from human clinical specimens and interactions with antimicrobial drugs.
The biological properties of medicinal plants have been documented worldwide for many centuries. We aimed to evaluate interactions between crude extracts from Psidium guajava, Zingiber officinale, Cymbopogon citratus, Caryophyllus aromaticus, Mikania glomerata and Allium sativum samples and antimicrobial drugs against Escherichia coli strains. The susceptibility test performed was disc diffusion, and crude extracts were diluted (%v/v) into Müller-Hinton agar (MHA) at one quarter of the minimal inhibitory concentration for 90% (MIC(90%)) of E. coli strains found previously. Synergistic interactions were observed between C. citratus and polymyxin, and A. sativum extracts and gentamicin. The crude A. sativum extract was the only one that did not show any antagonism with the antimicrobial drugs. The results thus showed the potential use of these medicinal plants against E. coli strains, although antagonism with antimicrobial drugs is a negative aspect in the combined therapy of infectious diseases caused by E. coli. PMID:22011190
Ushimaru, P I; Barbosa, L N; Fernandes, A A H; Di Stasi, L C; Fernandes, A
Computerized image analysis of full-hand touch plates: a method for quantification of surface bacteria on hands and the effect of antimicrobial agents.
A method is described for quantification of the bacterial flora on the hand surface. Computer-assisted image analysis of bacterial growth of large full-hand touch plates provides a quantifiable measure of the bacterial flora on the hand surface. Image analysis pixel intensity values showed a significant correlation (P less than 0.0001) with colony forming unit values determined by the glove juice method. Image analysis of impressions from hands treated with various antimicrobial agents in detergent bases showed that 4% chlorhexidine gluconate produces a 96% reduction after a 30 s washing and 98% reduction after a 3 min washing while 7.5% povidone-iodine and 1% triclosan produce a 77% and 70% reduction after 3 min respectively, and 70% isopropanol produces a 98% reduction after a 30 s wash. PMID:1679442
Leyden, J J; McGinley, K J; Kaminer, M S; Bakel, J; Nishijima, S; Grove, M J; Grove, G L
Phytochemical screening and antimicrobial activities of plant extract of Lantana camara.
Natural products continue to play an important role in the discovery and development of new pharmaceuticals. Several chemical compounds have been extracted and identified from its species known as Lantana camara (L .camara). The present study was designed for phytochemical analysis of L. camara and extraction of bioactive compound by HPLC. This also included the antimicrobial activity of the bioactive compound obtained by crude extract and the column extract. The study showed the presence of the bioactive component parthenin extracted from the HPLC analysis at a peak height of 10.3807 and it was showing antimicrobial activity against E. coli, P. aeruginosa, B. subtilis and E. fecalis, crude (6.8 to 8.1 mm ) and column (4.0 to 6.2 mm) zone of inhibition. PMID:24617153
Pradeep, B Vishwanath; Tejaswini, M; Nishal, P; Pardhu, G; Shylaja, S; Kumar, Kranthi Ch
Antibiotic conjugated fluorescent carbon dots as a theranostic agent for controlled drug release, bioimaging, and enhanced antimicrobial activity.
A novel report on microwave assisted synthesis of bright carbon dots (C-dots) using gum arabic (GA) and its use as molecular vehicle to ferry ciprofloxacin hydrochloride, a broad spectrum antibiotic, is reported in the present work. Density gradient centrifugation (DGC) was used to separate different types of C-dots. After careful analysis of the fractions obtained after centrifugation, ciprofloxacin was attached to synthesize ciprofloxacin conjugated with C-dots (Cipro @ C-dots conjugate). Release of ciprofloxacin was found to be extremely regulated under physiological conditions. Cipro @ C-dots were found to be biocompatible on Vero cells as compared to free ciprofloxacin (1.2?mM) even at very high concentrations. Bare C-dots ( ? 13?mg?mL(-1)) were used for microbial imaging of the simplest eukaryotic model-Saccharomyces cerevisiae (yeast). Bright green fluorescent was obtained when live imaging was performed to view yeast cells under fluorescent microscope suggesting C-dots incorporation inside the cells. Cipro @ C-dots conjugate also showed enhanced antimicrobial activity against both model gram positive and gram negative microorganisms. Thus, the Cipro @ C-dots conjugate paves not only a way for bioimaging but also an efficient new nanocarrier for controlled drug release with high antimicrobial activity, thereby serving potential tool for theranostics. PMID:24744921
Thakur, Mukeshchand; Pandey, Sunil; Mewada, Ashmi; Patil, Vaibhav; Khade, Monika; Goshi, Ekta; Sharon, Madhuri
[Measurement of chemical agents in metallurgy field: electric steel plant].
The steel industry maintains its important position in the context of the Italian production involving thousands of workers. The iron and steel processes are divided into primary steel industry, production of intermediate minerals, and secondary steel, scrap from the production of semi-finished industrial and consumer sector (metal inserted into components and metal used for dissipative uses, primarily coatings) and industrial waste. The paper presents the results of environmental monitoring carried out in some electric steel plant for the measurement of airborne chemicals that characterize the occupational exposure of workers employed in particular area like electric oven, to treatment outside the furnace, continuous casting area. For the sampling of the pollutants were used both personal and in fixed positions samplers. The pollutants measured are those typical of steel processes inhalable dust, metals, respirable dust, crystalline silica, but also Polycyclic Aromatic Hydrocarbons (PAH), polychlorinated dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PMID:23213795
Cottica, D; Grignani, E; Ghitti, R; Festa, D; Apostoli, P
Immunomodulating agents of plant origin. I: Preliminary screening.
The immunobiological activity was investigated of certain medicinal plants widely used in the Ayurvedic and Unani systems of medicine for treatment of chronic infections and immunological disorders. The effect of an ethanolic extract of each drug was studied on delayed type hypersensitivity, humoral responses to sheep red blood cells, skin allograft rejection, and phagocytic activity of the reticuloendothelial system in mice. Picrorhiza kurroa was found to be a potent immunostimulant, stimulating both cell-mediated and humoral immunity. Tylophora indica, Aconitum heterophyllum and Holarrhena antidysenterica appeared to stimulate phagocytic function while inhibiting the humoral component of the immune system. Tinospora cordifolia and Ocimum gratissimum appeared to improve the phagocytic function without affecting the humoral or cell-mediated immune system. Hemidesmus indicus suppressed both the cell-mediated and humoral components of the immune system. PMID:3560991
Atal, C K; Sharma, M L; Kaul, A; Khajuria, A
A potential of some medicinal plants as an antiulcer agents
Peptic ulcers are a broad term that includes ulcers of digestive tract in the stomach or the duodenum. The formation of peptic ulcers depends on the presence of acid and peptic activity in gastric juice plus a breakdown in mucosal defenses. There are two major factors that can disrupt the mucosal resistance to injury: non-steroidal antiinflammatory drugs (NSAIDs) example, aspirin and Helicobacter pylori infection. Numerous natural products have been evaluated as therapeutics for the treatment of a variety of diseases, including peptic ulcer. There has been considerable pharmacological investigation into the antiulcer activity of some compounds. In this work, we shall review the literature on different medicinal plant and alkaloids with antiulcer activity. This article reviews the antiacid/anti-peptic, gastroprotective and/or antiulcer properties of the most commonly employed herbal medicines and their identified active constituents. The experimental parameters used for antiulcer activity were cold restraint stress-induced ulcer model, Diclofenac-induced ulcer model in rats, (HCl–ethanol)-induced ulcer in mice and water immersion stress-induced ulcer in rats. The ideal aims of treatment of peptic ulcer disease are to relieve pain, heal the ulcer and delay ulcer recurrence. About 70% of patients with peptic ulcer disease are infected by Helicobacter pylori and eradication of this microorganism seems to be curative for this disease. This article reviews drugs derived from medicinal plant more commonly used in the world for peptic ulcer and, if reported, the antiulcer activity. This article will be concerned only with the antiulcer and gastro-protective effects.
Gadekar, R.; Singour, P. K.; Chaurasiya, P. K.; Pawar, R. S.; Patil, U. K.
The Potential of Antimicrobial Peptides as Biocides
Antimicrobial peptides constitute a diverse class of naturally occurring antimicrobial molecules which have activity against a wide range of pathogenic microorganisms. Antimicrobial peptides are exciting leads in the development of novel biocidal agents at a time when classical antibiotics are under intense pressure from emerging resistance, and the global industry in antibiotic research and development stagnates. This review will examine the potential of antimicrobial peptides, both natural and synthetic, as novel biocidal agents in the battle against multi-drug resistant pathogen infections.
Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.
Complicated schemes of classical breeding and their drawbacks, environmental risks imposed by agrochemicals, decrease of arable land, and coincident escalating damages of pests and pathogens have accentuated the necessity for highly efficient measures to improve crop protection. During co-evolution of host-microbe interactions, antimicrobial peptides (AMPs) have exhibited a brilliant history in protecting host organisms against devastation by invading pathogens. Since the 1980s, a plethora of AMPs has been isolated from and characterized in different organisms. Nevertheless the AMPs expressed in plants render them more resistant to diverse pathogens, a more orchestrated approach based on knowledge of their mechanisms of action and cellular targets, structural toxic principle, and possible impact on immune system of corresponding transgenic plants will considerably improve crop protection strategies against harmful plant diseases. This review outlines the current knowledge on different modes of action of AMPs and then argues the waves of AMPs' ectopic expression on transgenic plants' immune system.
Quinones derived from plant secondary metabolites as anti-cancer agents.
Quinones are plant-derived secondary metabolites that present some anti-proliferation and anti-metastasis effects in various cancer types both in vitro and in vivo. This review focuses on the anti-cancer prospects of plant-derived quinones, namely, aloe-emodin, juglone, ?-lapachol, plumbagin, shikonin, and thymoquinone. We intend to summarize their anti-cancer effects and investigate the mechanism of actions to promote the research and development of anti-cancer agents from quinones. PMID:22931417
Lu, Jin-Jian; Bao, Jiao-Lin; Wu, Guo-Sheng; Xu, Wen-Shan; Huang, Ming-Qing; Chen, Xiu-Ping; Wang, Yi-Tao
Culturable Leaf-Associated Bacteria on Tomato Plants and Their Potential as Biological Control Agents
Culturable leaf-associated bacteria inhabiting a plant have been considered as promising biological control agent (BCA) candidates\\u000a because they can survive on the plant. We investigated the relationship between bacterial groups of culturable leaf-associated\\u000a bacteria on greenhouse- and field-grown tomato leaves and their antifungal activities against tomato diseases in vitro and in vivo. In addition, the isolated bacteria were analyzed for
Junichiro Enya; Hirosuke Shinohara; Shigenobu Yoshida; Takao Tsukiboshi; Hiromitsu Negishi; Kazuo Suyama; Seiya Tsushima
Evidence against a direct antimicrobial role of H2O2 in the infection of plants by Erwinia chrysanthemi.
We have investigated the role of bacterial resistance to oxidative stress in pathogenesis. The oxyR gene from the pathogenic bacterium Erwinia chrysanthemi has been characterized. It is closely related to that found in Escherichia coli (88% overall amino acid identity). An E. chrysanthemi oxyR mutant strain was constructed by marker exchange. After induction with a sublethal dose of H2O2, this mutant was more sensitive to H2O2 and showed reduced levels of catalase and glutathione reductase activities, compared with the wild type. The oxyR mutant was unable to form individual colonies on agar plates unless catalase was added exogenously. However, it retained full virulence in potato tubers and tobacco leaves. These results suggest that the host-produced H2O2 has no direct antimicrobial effect on the interaction of E. chrysanthemi with the two plant species. PMID:10755305
Miguel, E; Poza-Carrión, C; López-Solanilla, E; Aguilar, I; Llama-Palacios, A; García-Olmedo, F; Rodríguez-Palenzuela, P
Antimicrobial activity of an Amazon medicinal plant (Chancapiedra) (Phyllanthus niruri L.) against Helicobacter pylori and lactic acid bacteria.
The potential of water extracts of the Amazon medicinal plant Chancapiedra (Phyllanthus niruri L.) from Ecuador and Peru for antimicrobial activity against Helicobacter pylori and different strains of lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus plantarum was investigated. H. pylori was inhibited by both water extracts in a dose dependent manner, whereas lactic acid bacterial growth was not affected. Both extracts contained ellagic acid and hydroxycinnamic acid derivatives and exhibited high free radical scavenging linked-antioxidant activities (89%). However, gallic acid was detected only in the Ecuadorian extract. Preliminary studies on the mode of action of Chancapiedra against H. pylori revealed that inhibition may not involve proline dehydrogenase-based oxidative phosphorylation inhibition associated with simple mono-phenolics and could involve ellagitannins or other non-phenolic compounds through a yet unknown mechanism. This study provides evidence about the potential of Chancapiedra for H. pylori inhibition without affecting beneficial lactic acid bacteria. PMID:22034238
Ranilla, Lena Gálvez; Apostolidis, Emmanouil; Shetty, Kalidas
Contrasting effects of two antimicrobial agents (triclosan and triclocarban) on biomineralisation of an organophosphate pesticide in soils.
We examined the impact of triclosan (TCS) and triclocarban (TCC) antimicrobial compounds on the biomineralisation of glucose and cadusafos pesticide in three Australian soils. Mineralisations of radiolabelled ((14)C) compounds were measured over a period of up to 77d in sterile and non-sterile soils treated with different concentrations of TCS and TCC (0-450mgkg(-1)). The rates of mineralisation of cadusafos were found to decrease with increasing concentration of TCS in all soils, but varied with soil type. Soils treated with TCS at the highest concentration (270mgkg(-1)) reduced cadusafos mineralisation by up to 58%. However, glucose mineralisation was not significantly affected by the presence of TCS. While TCS, significantly reduced the mineralisation of cadusafos (by 17%; p<0.05) even at the lowest studied concentration (30mgkg(-1)), no significant effect of TCC was observed on cadusafos or glucose mineralisation even at the highest concentration used (450mgkg(-1)). PMID:24461429
Kookana, R S; Ali, A; Smith, L; Arshad, M
Lipooligosaccharide Structure is an Important Determinant in the Resistance of Neisseria Gonorrhoeae to Antimicrobial Agents of Innate Host Defense
The strict human pathogen Neisseria gonorrhoeae has caused the sexually transmitted infection termed gonorrhea for thousands of years. Over the millennia, the gonococcus has likely evolved mechanisms to evade host defense systems that operate on the genital mucosal surfaces in both males and females. Past research has shown that the presence or modification of certain cell envelope structures can significantly impact levels of gonococcal susceptibility to host-derived antimicrobial compounds that bathe genital mucosal surfaces and participate in innate host defense against invading pathogens. In order to facilitate the identification of gonococcal genes that are important in determining levels of bacterial susceptibility to mediators