Lipopeptides and lipoglycopeptides: As the name suggests, lipopeptides consist of a lipid moiety attached to peptide molecules. Daptomycin, which gained US FDA approval in 2003, 285 remains the only lipopeptide that is currently in use against Gram-positive bacteria. Structurally, daptomycin is a cyclic lipopeptide consisting of 13 amino acids out of which 10 amino acids form a macrolide ring. Over the years, structure-activity relationship (SAR) efforts have been made to identify structural features required for daptomycin's antibacterial effect and to try and improve them. Daptomycin functions by disrupting the bacterial cell membrane directly by binding to phosphatidylglycerol and in an indirect manner by tampering with the synthesis of peptidoglycans with the antibacterial effect observed appearing to be dependent on the presence of and binding with calcium. Other examples of calcium-dependent antibiotics 294 include lipopeptides isolated and purified from natural sources such as octapeptins, 295 friulimicin B 296 and amphomycin among others. Octapeptins-which are cyclic lipopeptides, function by inserting into bacterial cell membrane, they have shown an increase in interest, especially in the last 5 years or so with efforts being made to systematically study them in order to design newer and more efficacious analogs. Lipoglycocpeptides consist of carbohydrate and lipid moieties attached to peptide molecules. Examples of US FDA-approved lipoglycopeptides include telavancin, 304 dalbavancin, and oritavancin. The lipoglycopeptide class of antibiotics tends to act via bacterial cell wall disruption by interfering in the synthesis of peptidoglycans 309 similar to glycopeptides such as vancomycin. Most likely as a result of the large size, lipoglycopeptides tend to be absorbed poorly upon oral administration and have to be administered intravenously. They tend to be longacting with half-lives in the range of several hours. A recent study highlighted lower healthcare costs associated with the treatment of recurrent and serious bacterial infections in individuals with substance use disorder with long acting lipoglycopeptide 312 and a 2020 review described similar outcomes/findings. 313 Bacteriophages: Bacteriophages are viruses capable of targeting and destroying bacterial cells selectively. While the discovery of bacteriophages can be traced back to the late 1800s, their subsequent development was overshadowed by the discovery and popularization of antibiotics. Broadly speaking the lytic cycle of bacteriophages involves the following major steps: (i) attachment to bacterial cells via receptors, (ii) injection of viral DNA into bacterial cells, (iii) replication of viral proteins and components within bacterial cells, (iv) packing and release of replicated viruses after bacterial cell lysis. The exact series and mechanism of events may differ depending on the bacteriophage and the host bacterial cell. In contrast in a lysogenic cycle, incorporation of viral DNA into host DNA occurs. Bacteriophages tend to be specific in terms of the receptors they interact with and the species they can affect/target. Advantages associated with bacteriophage therapy include: effectiveness against MDR bacteria , specificity in terms of species and/or strains, and leaving the patient's gut microbiome largely unaltered. Furthermore, bacteriophage therapy has been shown to have an excellent safety profile in human beings. All of these features mean that as the threat of MDR strains becomes more imminent, bacteriophage therapy has seen a promising resurgence in interest. In a recent study, a group of researchers designed and administered personalized bacteriophage therapy to an individual suffering from lung infection caused by MDR Pseudomonas aeruginosa and appeared to be successful in stopping antibiotic therapy completely. Other instances of successful personalized bacteriophage therapy against MDR strains have also been reported. However, there are still challenges that need to be addressed in order to make bacteriophage therapy more viablepoor in vivo efficacy in terms of targeting bacterial species in the gut upon oral administration is an important one. There are also noted instances of resistance against bacteriophages though their prevalence is far lower than antibiotic resistance. Microbiota Interventions/Probiotics: The use of antibiotics kills not only disease-causing bacterial species but other beneficial bacterial species prevalent in the human gut. Alteration of the complex and dynamic gut microbiota has been increasingly linked to several diseases including mental health disorders. Furthermore, evidence suggests that disruptions/alterations of the gut microbiome following antibiotic therapy can be long-lasting from anywhere between weeks to up to several months. It has been shown that co-administration of probiotics along with antibiotics could be beneficial to counter the negative impact of antibiotics on the gut microbiome. Consequently, this practice is becoming more prevalent and popular; however, there have been concerns raised about the actual benefit of consuming probiotics in rebalancing the gut microbiome. 3.3. The importance of anti-biofilm materials Biofilms are a complex community of mono-species or multispecies microbes that are attached to a surface and to each other and are embedded in a self-produced extracellular matrix that consists of proteins, polysaccharides, and environmental DNA. This allows bacteria to withstand hostile environments, and starvation desiccation, and is protected from fluctuations in humidity, temperature, pH, etc. Bacteria in biofilms can evade the host defense systems and can cause local tissue damage and acute infection. These biofilms can develop in catheters, pacemakers, joint prostheses, dentures, contact lenses, prosthetic heart valves, and implants. Biofilms also protect bacteria and increase bacterial resistance against conventional antibiotics. Dry surface biofilms, which might contribute to healthcare-acquired infections, can be difficult to remove and allow bacteria to tolerate or resist attacks by other pathogens, disinfectants, antiseptics, heavy metals, and other antimicrobial agents. This means that the development of new anti-microbial materials that also have anti-biofilm properties is of utmost importance in the healthcare industry.