Phenotypic and Genotypic Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumonia isolates from Patient’s Urine specimens

Introduction: Extended-spectrum β-lactamases (ESBL)-producing Enterobacteriaceae are a clinical threat that may cause nosocomial as well as community-acquired infections. E.coli and Klebsiella are among the most common Gram-negative bacilli causing urinary tract infections. Aim of the study: Molecular confirmation of ESBL production among phenotypically proved ESBL-producing E.coli and Klebsiella. Materials and Methods: A total of 64 community and hospital-acquired Enterobacteriaceae suspected to produce ESBLs by routine antimicrobial susceptibility test. Identification of species of Enterobacteriacea was done by the API 20E identification system. ESBL production was detected by double disc synergy test (DDST) followed by detection of the encoding genes by PCR using primers for bla-TEM, bla-CTX-M1, bla-CTX-M2, bla-SHV and bla-PER genes. Results: E.coli (n=40) and Klebsiella pneumonie (n=24) were identified by API 20E. Fourty nine isolates were positive for ESBL-production by DDST. Fifty seven isolates proved to produce ESBLs by PCR. The bla-TEM, bla-CTX-M1 and bla-PER were the most prevalent ESBL genes detected by PCR. Conclusion: The double disc synergy test showed sensitivity of 82.5% in relation to PCR. The study showed high prevalence of ESBLs in E.coli and Klebsiella pneumonie with bla-TEM, bla-CTX-M1 and bla-PER as the predominant ESBL genes. Key words: E.coli, Klebsiella pneumonie, ESBL, DDST, PCR.