Frequency and resistance pattern of extended spectrum beta lactamase producing Escherichia coli in clinical specimen of Alzahra hospital in Isfahan, Iran, 2007

Infection by drug resistant organisms such as Extended-spectrum beta lactamase (ESBL)-producing Escherichia coli have caused major therapeutic problems. In this study, prevalence of ESBL positive Escherichia coli in clinical specimens was studied and their antibiotic-resistant patterns were evaluated. In a descriptive analytical study, 278 clinical isolates of Escherichia coli were obtained from Alzahra hospital in Isfahan, Iran. Phenotypic confirmatory test was used to detect ESBL-producing isolates. The antibiotic susceptibility patterns of ESBL producing isolates were determined using disk diffusion method following the recommendations of the NCCLS. Data were analyzed and evaluated by using Chi-square test. Among 278 clinical isolates, 150 isolates (53.9%) produced ESBL. All strains were susceptible to imipenem and meropenem. Comparing antibiotic resistance between ESBL producing strains and non-ESBL producing strains, significant differences were obtained for quinolones, and amino glycosides. Our study showed high prevalence of ESBL strains (53.9%). More over, most of the ESBL strains were also resistant to quinolones and amino glycosides. Based on our finding, it is recommended that prescription of cephalosporins should be restricted to susceptible isolates. Diagnose of ESBL strains in clinical laboratory also should be considered.