DETERMINATION OF THE EFFICACY OF PHOSPHOMYCIN ON IMIPENEM RESISTANT KLEBSIELLA PNEUMONIAE CLINICAL ISOLATES

Multiple drug resistance among Klebsiella pneumoniae isolates is one of the most
important challenges for treating of such infections. Fosfomycin is a broad-spectrum peptidoglycan
biosynthesis inhibitor. The purpose of this study was to evaluate the effect of fosfomycin on imipenem
resistant clinical isolates of Klebsiella pneumoniae.
Materials & Methods: This study included 43 isolates of imipenem resistant Klebsiella pneumoniae
were collected from educational hospitals of Urmia and were identified by using the standard methods.
Susceptibility of isolates to various antibiotics was determined by disk diffusion method. The minimum
inhibitory and minimum bactericidal concentrations of fosfomycin were determined in the range of 8-
1024 mg/mL.
Results: All tested isolates were resistant to fosfomycin. The minimum inhibitory and bactericidal
concentrations for investigated isolates were determined in the range of 512-1024 mg/mL. According
to EUCAST criteria if the minimum inhibitory concentration of antibiotic for an isolate is equal or
greater than 32μg / mL, the isolates were considered as resistant to fosfomycin, so all the isolates were
defined as resistant to this antibiotic.
Conclusion: In spite of the fact that some of the other studies confirmed the effectiveness of this
antibiotic in treatment of Enterobacteriaceae caused infections, at least in the studied area fosfomycin is
inefficient for treating of infections caused by imipenem resistant Klebsiella pneumoniae isolates.