Antimicrobial resistance patterns of Clostridium difficile strains isolated from Marmara University Hospital

Objective: This study was designed to investigate antimicrobial resistance patterns of toxigenic Clostridium difficile strains isolated from Marmara University Hospital. Methods: The stool specimens ordered for detection of Clostridium difficile toxin at the Microbiology Laboratory, between April 2008 and January 2010 were cultured anaerobically. The antimicrobial susceptibility of the isolated 50 toxigenic Clostridium difficile strains was determined using the agar dilution protocol in the CLSI guidelines (M11-A7). The investigated antibiotics were metronidazole, vancomycin, meropenem clindamycin, and ampicillin. Breakpoints of susceptibility for each drug were considered according to the levels listed by the CLSI, intermediate strains evaluated as resistant ones. Results: All isolates were sensitive to metronidazole, vancomycin and meropenem. Resistance rates to clindamycin and ampicillin were 62% and 68%, respectively. Conclusion: For now there seems to be no resistance risk for metronidazole and vancomycin, the two agents commonly used to treat Clostridium difficile-associated diarrhea. Our findings determine the current antibiotic susceptibility patterns of the Clostridium difficile isolates in our region and also in Turkey, where clinical laboratories do not routinely perform culture and susceptibility testing of the organism.