ORIGINAL ARTICLE Susceptibility of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Urine

Aim: Urinary tract infections (UTIs) caused in particular by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains are related with high morbidity and mortality, and treatment is quite difficult. These infections generally are treated by carbapenems, and their costs are high. We aimed in this study to investigate the susceptibilities of ESBL-producing E. coli strains isolated from urine cultures to fosfomycin, ciprofloxacin, amikacin and trimethoprim-sulfamethoxazole and to determine the general resistance profile in our region of these strains isolated from UTIs. Materials and Methods: Between January 2005-December 2005, ESBL-producing E. coli strains isolated from urine samples sent from various outpatient and inpatient clinics to the Bacteriology Laboratory of the Department of Microbiology and Clinical Microbiology were included prospectively in the study. ESBL production was detected using the double disk synergy test. Antibiotic susceptibility testing was performed for ESBL-producing isolates by disk diffusion test according to Clinical and Laboratory Standards Institute (CLSI) criteria. Escherichia coli ATCC 35218 and ATCC 25922 were used as control strains. The diagnosis of nosocomial UTIs was established according to the Centers for Disease Control and Prevention criteria. The data were assessed using the SPSS 11.0 packet program. Results: A total of 344 ESBL-producing E. coli isolates (241 nosocomial isolates; 103 outpatient isolates