Authors
1 Department of Microbiology, Faculty of Biological Sciences, Shahid Beheshti University
2 Associate Professor of Microbiology, Faculty of Biological Sciences, Shahid Beheshti University
3 65 / 5000 Translation results Professor, Department of Microbiology, School of Medicine, Iran University of Medical Sciences
Abstract
Klebsiella pneumoniae is an opportunistic pathogen that causes a significant proportion of community and hospital acquired infections. Among the antibiotic classes, β -lactams are often used for treatment of these infections. However, bacterial resistance has developed mostly due to the production of a variety of β-lactamases, especially the extended-spectrum β-lactamases (ESBL). In this research, one hundred and ninety six K. pneumoniae isolates were collected from Imam Hussein Hospital in Tehran during 2008-2012. Antibiotic susceptibility was determined by disc diffusion and extended-spectrum β-lactamase production was shown by the phenotypic confirmatory test. Carriage of blaSHV, blaTEM and blaCTX-M genes was detected by PCR and specific primers. ESBL production was examined in relation to the presence of blaSHV, blaTEM and blaCTX-M genes. Overall, 160 isolates (81.6 %) carried blaCTX-M, 104 (53.06 %) had blaTEM and 82 (41.8%) harbored the blaSHV genes. ESBL production was observed in 92 isolates (46.9%) of which, 77 (83.6 %) harbored blaCTX-M, 57 (61.9 %) had blaTEM and 43 (46.7%) carried blaSHV. Finally, 7 (7.6 %) did not harbour any of the 3 genes and 24 (26.08%) carried all three. Our results show that gene carriage does not necessarily account for its expression and ESBL phenotype. In addition, the presence of blaCTX -M was dominant in our urinary Klebsiella pneumoniae isolates followed by blaTEM and blaSHV .
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