Carbapenems resistance among Bacteroides fragilis isolatedfrom skin and soft tissue infections

Background and Aim : The carbapenem susceptibility pattern of Bacteroides fragilis isolatedfrom skin and soft tissue infections were investigated.Methods : Twenty- Six B. fragilis isolated was isolated from skin and soft tissue infections. Thestandard microbiological and biochemical tests were used for identification of isolates. Agardilution methods were applied for determine the susceptibility to imipenem according to theclinical and laboratory standards institute (CLSI). The presence of Metallo-β-lactamase (MBLs)and efflux pump mediated resistance were detected by phenotypic methods.Results : According to the minimum inhibitory concentration (MIC), ۴ isolates were imipenemresistant (MIC ≥ ۱۶ μg/mL). The imipenem MIC ranges were ۲-۶۴ μg/mL in bacterial isolates.The MIC۵۰ and MIC۹۰ of imipenem were ۸ μg/mL and ۱۶ μg/mL, respectively. The MBLsmediated resistance was detected in all imipenem resistant isolates. Efflux pump mediatedresistance was detected in ۱ isolates that was MBLs positive.Conclusion : According to our results the incidence of carbapenems resistant B. fragilis is at aworrying level. The most common mechanism of carbapenems resistance among B. fragilis wascarbapenemase production. The resistance to carbapenem may be multifactorial in some B. fragilisisolates. We propose reassessment in the controlling program of anaerobic pathogens in our healthcare centers.

کلیدواژه ها:

Bacteroides fragilis ، Carbapenem ، Metallo-β-lactamase ، efflux pump