although recent data on the routes of infection are inconsistent , it is assumed that the majority of bacterial infections is caused by endogenous organisms or acquired gram - negative bacteria which colonize the gastrointestinal tract . therefore , prophylactic selective bowel decontamination ( sbd ) using non - absorbable antibacterial and antifungal agents is applied in patients undergoing bone marrow transplantation in some hospitals , although the value of this measure is controversial , . like other aminoglycoside compounds , paromomycin ( aminosidine ) is poorly absorbed from the gastrointestinal tract . previously , we have published the observation that bacteremia with enterobacteriaceae is observed less frequently in neutropenic patients with previous sbd using paromomycin , whereas there is no difference with regard to bacteremia with non - fermenting gram - negative bacilli . in this context , the aim of the present study was to investigate the in vitro activity of paromomycin against e. coli and p. aeruginosa . e. coli isolates ( n=94 ) were obtained from stool / rectal swabs ( n=69 ) , urine ( n=10 ) , respiratory tract ( n=9 ) , blood ( n=4 ) , and wound swabs ( n=2 ) . p. aeruginosa isolates ( n=77 ) were derived from stool / rectal swabs ( n=5 ) , respiratory tract ( n=6 ) , blood ( n=60 ) , and wound swabs ( n=6 ) . identification was performed with api 20e ( biomrieux , marcy letoile , france ) for e. coli , and with culture on cetrimide agar plates ( pseudosal ; becton dickinson , heidelberg , germany ) and inspection under uv - light combined with api 20ne ( biomrieux ) for p. aeruginosa . the mics for both compounds were determined according to the recommendations of the clinical laboratory standards international ( clsi ) for testing amikacin . the atcc reference strains 25922 ( e. coli ) and 9027 ( p. aeruginosa ) were used for quality control . the mics for paromomycin and amikacin against e. coli and p. aeruginosa , respectively , are shown in table 1 ( tab . , 86 of 94 e. coli isolates ( 91% ) and 71 of 77 p. aeruginosa isolates ( 92% ) showed in vitro susceptibility to amikacin ( mic90 for both compounds : 16 g / ml , range : 132 g / ml for e. coli and 1>128 g / ml for p. aeruginosa ) . paromomycin was active against 83/94 e. coli isolates ( 88% ; mic90 : 32 g / ml , range : 2>128 g / ml ) , but showed poor in vitro activity against p. aeruginosa ( 3/77 isolates susceptible [ 4% ] ; mic90 : > 128 g / ml , range : 2>128 g / ml ) . paromomycin , which was first isolated in 1956 , is a member of the aminoglycoside family . infections , and has been proposed as a treatment for giardia lamblia in resistant infections and during pregnancy . furthermore , it is used for prophylaxis of hepatic encephalopathy in patients with liver cirrhosis . paromomycin is also used for sbd in patients undergoing bone marrow transplantation in some centers , , . in addition , paromomycin is frequently recommended for the use in sbd by non - peer reviewed media , at least in the german - speaking countries . amikacin resistance in e. coli and p. aeruginosa was found to be in agreement with previously published data in the present study is . an analysis of more than 4,000 clinical isolates from patients with bloodstream infections in the united states revealed that 98.5% of e. coli isolates and 98.4% of p. aeruginosa isolates were susceptible to this agent . 94.4% of p. aeruginosa blood culture isolates in vienna university hospital are susceptible to amikacin . due to the lack of published in vitro resistance data for paromomycin , no trend in paromomycin resistance can be deduced from the present results . in addition , it is unknown which mechanisms lead to clinically relevant resistance against paromomycin . generally , bacterial resistance to aminoglycosides may be due to decreased antibiotic uptake and accumulation , modification of the ribosomal target , and efflux of the antibiotic , but the enzymatic modification of aminoglycosides is thought to be the most important mechanism of aminoglycoside resistance in clinical isolates . three families of enzymes that perform cofactor - dependent drug modification in the bacterial cytoplasm have been recognized ; these are aminoglycoside phosphotransferases ( aphs ) , aminoglycoside acetyltransferases ( aacs ) , and aminoglycoside nucleotidyltransferases ( ants ) . some enzymes ( i.e. aph(3')-i , aph(3')-iii , and aac(1 ) ) have been shown to produce paromomycin resistance , while they are not implicated in amikacin resistance . in conclusion , if sbd with inclusion of an aminoglycoside antibiotic is applied , paromomycin should not be used unless local resistance data provide evidence of a sufficient in vitro activity of this compound against p. aeruginosa .
background : paromomycin is used for selective bowel decontamination ( sbd ) in patients undergoing bone marrow transplantation in many hospitals , but there are no published resistance data for this compound in the recent medical literature . 
 the aim of this study was to investigate the in vitro activity of paromomycin against the common intestinal bacteria e. coli and p. aeruginosa.methods : 94 e. coli isolates and 77 p. aeruginosa isolates derived from clinical specimens were tested by broth microdilution against paromomycin and amikacin , respectively , following the clsi recommendations for testing amikacin.results : 86 of 94 e. coli isolates ( 91% ) and 71 of 77 p. aeruginosa isolates ( 92% ) showed in vitro susceptibility to amikacin ( mic90 for both compounds : 16 g / ml , range : 132 g / ml for e. coli and 1>128 g / ml for p. aeruginosa ) . 
 paromomycin was active against 83/94 e. coli isolates ( 88% ; mic90 : 32 g / ml , range : 2>128 g / ml ) , but showed poor in vitro activity against p. aeruginosa ( 3/77 isolates susceptible [ 4% ] ; mic90 : > 128 g / ml , range : 2>128 g / ml).conclusion : if sbd with inclusion of an aminoglycoside antibiotic is applied , paromomycin should not be used unless local resistance data provide evidence of a sufficient in vitro activity of this compound against p. aeruginosa .