Frequency of Resistance to Common Antibiotics in Iranian Clostridium Difficile Clinical Isolates

Every year، gastrointestinal infections cause significant morbidity and mortality throughout the world. According to the World Health Organization، more than four billion cases of diarrheal diseases occur annually. Hence، diarrheal diseases are known as the fifth leading cause of death in all ages around the world. Clostridium difficile is the causative agent of severe intestinal diseases in hospitalized patients. It causes severe diarrhea and colitis in both adults and children. The aim of this study was to determine the frequency of resistance to common antibiotics like metronidazole، ceftazidime، ciprofloxacin، imipenem and amikacin in clinical isolates of C. difficile in Iran. Eighty six C. difficile isolates from fecal samples of patients suspicious to antibiotic-associated diarrhea (AAD) were cultured on specific medium. Genomic DNA was then extracted and used for polymerase chain reaction (PCR) of C. difficile toxins (tcdA and tcdB) and cdd3 gene. Afterward، they were confirmed with molecular pathway. Susceptibility of the isolates to five different antibiotics was determined by disc diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Resistance to ceftazidime، amikacin، imipenem and ciprofloxacin was observed in 82 (96%)، 81 (94%)، 76 (88%)، and 60 (70%) samples، respectively. No metronidazole-resistant isolate was found. High levels of resistance to the studied antibiotics was seen among the clinical isolates of C. difficile in Iran. Considering the medicines prescribed for AAD and the antibiotic resistance pattern in Iran، metronidazole seems to be effective for treating C. difficile infection among Iranian patients. Constant monitoring of antimicrobial susceptibility over different spectrums for common therapeutic regimens against bacterial infections is necessary to prevent the spread of resistant isolates.