Antimicrobial resistance surveillance among hospitalized and non-hospitalized extend-spectrum beta-lactamase producing Escherichia coli from four tertiary-care hospitals in Isfahan, Iran; 2008-2011

For the first time we launched a prospective laboratory-based Antimicrobial Resistance Surveillance System in Isfahan province, Iran. In a cross-sectional study prevalence of ESBL (extend-spectrum beta-lactamase) producing Escherichia coli isolates and their antimicrobial susceptibility patterns according to CLSI (Clinical and Laboratory Standards Institute) guideline were studied in four tertiary-care hospitals from January 2008 to February 2011. Data were extracted from the participating hospital and converted centrally into a standard format using WHONET 5.6 software (WHO, Geneva, Switzerland). Among a total of 2035 consecutive clinical isolates identified as E. coli, 898 (44.1%) and 432 (21.2%) were ESBL producers for hospitalized and non-hospitalized patients respectively (95% confidence intervals: 1.3771 to 2.013, Odds ratio: 1.6649, P<0.0001). Two studied hospitals presented 64 and 56% ESBL producing E. coli. The both non-hospitalized and hospitalized isolates were more resistant to ampicillin (84.4 and 94.9% respectively), trimethoprim/sulfamethoxazole (60.1 and 84.8% respectively) and cefazolin (42 and 72.2% respectively). In non-hospitalized isolates, nitrofurantoin (with only 10.2% resistant) and ciprofloxacin (31%) were the effective antibiotics. Imipenem (2.5%), amikacin (17%) and nitrofurantoin (23.1%) were the effective antibiotics against hospitalized E. coli isolates recommended these agents as the first choices for patients’ treatment. Our results showed importance of continued antibiotic surveillance that will provide succession in the efforts of infection control programs for the future.

Antibiotic sensitivity pattern, Antimicrobial resistance surveillance, ESBL producing Escherichia coli, WHONET 5.6 software.