In vitro antimicrobial activity of fosfomycin against gram-negative bacilli

【Objective】 To determine the in vitro activity of fosfomycin against gram-negative bacilli.【Methods】 Antimicrobial susceptibility of clinical isolates was tested by kirby-Bauer method.【Results】 The resistant rates of E.coli,K.pneumoniae,Enterobacter cloacae and Enterobacter aerogenes to fosfomycin were 10% to 22%.The resistant rates of other Enterobacteriaceae,Paeruginosa and A.baumannii to fosfomycin were 35% to 41%,71% and 95% respectively.The resistant rate(22%) of ESBLs-producing K.pneumoniae to fosfomycin was higher than that(4%) of non-ESBLs producing strains.The bacteriostatic circle diameter of fosfomycin in E.coli susceptibilitic strains were bigger than that in K.pneumoniae.【Conclusions】 Fosfomycin can be selected against infections caused by ESBLs-producing E.coli,K.pneumoniae,Enterobacter cloacae and Enterobacter aerogenes but can not be selected against infections caused by nonfermenting gram-negative bacilli.The in vitro antimicrobial activity of fosfomycin in E.coli was higher than that in K.pneumoniae.