The prevalence and molecular characterization of extended-spectrum β- lactamases-producing Klebsiella pneumoniae isolates recovered from Kashan hospital university, Iran

Introduction and objective: Klebsiella is an opportunistic pathogen that is an important cause of nosocomial infections. The prevalence of extended spectrum beta-lactamases (ESBLs)-producing strains and their resistance to betalactam antibiotics has had a daily increase. Because of the importance of these enzymes in Klebsiella pneumonia, this study was carried out to investigate it’s prevalence in Shahid Beheshti hospital of Kashan. Materials and methods: This descriptive study was done on clinical samples collected from different wards of Shahid Beheshti hospital of Kashan. K. pneumonia was isolated on the basis of standard procedures and ESBLs producing strains were confirmed by double disk diffusion method. Extracted DNAs were investigated using specific primers for SHV-1 and TEM-1 genes by PCR method. Results: Thirty two percent of all 100 isolated K. pneumonia had ESBL phenotype. Seven (21.8%) of isolates contained both SHV-1 and TEM-1 genes. Twelve (37.5%) had just TEM1 gene and 16(50%) had SHV1 gene. Conclusion: Type and amount of antibiotic consumption and length of hospital stay has direct correlation with ESBL production. Because of more morbidity and mortality caused by ESBL isolates compared with infections caused by non-ESBL-producing organisms for treatment of a serious infection caused by an isolate confirmed for ESBL production, a carbapenem agent is indicated despite reports of treatment success with extended-spectrum cephalosporins.