Antibiotic resistance pattern in Shiga toxin-producing Escherichia coli isolated from diarrheal patients in Al-zahra Hospital, Isfahan, Iran.

Shiga toxin-producing Escherichia coli (STEC) can cause a broad spectrum of human illness. The progressive increase in antibiotic resistance among enteric pathogens in developing countries is becoming a critical area of concern. The aim of current study was to determine bacterial resistance pattern of a group of diarrheagenic E. coli to some important antibiotics. The research method was descriptive and observational. Isolates of STEC were assessed for susceptibility based on minimum inhibitory concentration method (MIC). MICs were determined by the broth dilution method following the recommendations of the National Committee for Clinical Laboratory, Standards (NCCLS).Of the 29 STEC isolates, 65.5, 72.4, 58.6, 27.6, 13.8, 20.7, 6.9 percentage were resistant to amoxicillin, trimethoprim-sulfamethoxazole, tetracycline, cefazolin, ceftriaxon, nalidixic acid and ciprofloxacin respectively and all were sensitive to ofloxacin. More than 66% of STEC strains were resistant to the 3 commonly used antibiotics with high MIC90s. According to our study, amoxicillin, tetracycline, and trimethoprim-sulfamethoxazole are not recommended for the treatment of diarrhea in this population. Therefore, regional information regarding antibiotic resistance should be used in clinical management, and treatment guidelines should be updated