Extended spectrum beta-lactamase (ESBL) production and antibiotic resistances of Escherichia coli and Klebsiella spp. strains isolated from urine cultures

Abstract

Objective: It was aimed to determine extended spectrum beta-lactamase (ESBL) production and antibiotic resis­tance rates of Escherichia coli and Klebsiella spp. strains isolated from urine cultures of patients admitted to vari­ous outpatient clinics and inpatient clinics of our hospital between December 2011 and August 2012. Methods: E.coli and Klebsiella spp. strains isolated from urine cultures were identified by conventional methods. Antibiotic susceptibilities were determined by using Kirby- Bauer’s disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) recommendations. Extended spectrum beta-lactamase (ESBL) producing E.coli and Klebsiella spp. strains were detected by using “double disk sinergy method”. Results: During the study period, 308 E.coli and 54 Kleb­siella spp. strains were isolated from urine cultures. ESBL production was detected in 64 (20.8%) of E.coli strains and 21 (38.9%) of Klebsiella spp. strains. ESBL positivity was encountered the most frequently in urine samples of patients who were from outpatient clinics of pediatrics and urology, it was followed by internal clinics and intensive care units. Imipenem resistance was found to be 4.7% and amikacin resistance was 7.8% in ESBL-positive E.coli strains. There was no resistance to carbapenems in ESBL-positive Klebsiella spp. strains, but their amika­cin resistance was 4.8%. Piperacillin tazobactam resis­tance rate in ESBL-positive E.coli and Klebsiella spp. was 17.2% and 14.3%, respectively. Conclusion: Selection of antibiotics should be made by considering results of antibiotic susceptibility tests for treatment of urinary tract infections. Also, determination of ESBL production and reporting it with antibiotic suscep­tibility tests will enhance the success of treatment.