Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Phenotypic and molecular characterization of plasmid-encoded extended spectrum beta-lactamases produced by Escherichia coli and Klebsiella spp from Lahore, Pakistan

Saba Riaz^1,2 , Muhammad Faisal Bashir²

¹Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590; ²Division of Microbiology, Citi Lab and Research Centre, 525 A Faisal Town, Lahore, Pakistan.

For correspondence:- Saba Riaz Email: saba.mmg@pu.edu.pk Tel:+923214530648

Received: 14 May 2015 Accepted: 8 August 2015 Published: 29 September 2015

Citation: Riaz S, Bashir MF. Phenotypic and molecular characterization of plasmid-encoded extended spectrum beta-lactamases produced by Escherichia coli and Klebsiella spp from Lahore, Pakistan. Trop J Pharm Res 2015; 14(9):1597-1604 doi: 10.4314/tjpr.v14i9.8

© 2015 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To investigate the distribution of plasmid-encoded extended spectrum beta-lacatamases (ESBLs) in Lahore, Pakistan using different phenotypic and molecular methods.

Methods: Escherichia coli and Klebsiella spp were obtained over a period of nineteen months (June 2007 to December 2008). Both were tested by the double disk synergy test, combined disk test and Epsiometer-test (E-test) to evaluate their ability to detect ESBLs. The genotypes of ESBLs were analyzed by monoplex polymerase chain reaction (PCR), multiplex PCR, DNA sequencing and isoelectric focusing.

Results: 662 E. coli and 153 Klebsiella spp were analyzed. Among these isolates, 39.3 % E. coli and 26.1 % Klebsiella spp were positive for extended spectrum beta-lactamases (ESBLs).71.9 % E. coli and 79.6 % Klebsiella spp showed minimum inhibitory concentration (MIC) in the range > 32/0.064 = 500 μl/mL for cetatzidime/cetatzidime + clavulanic acid, while 66.5 % E. coli and 69.1 % Klebsiella spp revealed MIC in the range of > 16/0.016 = 1000 μl/mL for cefotaxime/cefotaxime + clavulanic acid. Antibiotic susceptibility testing revealed that imipemem, meropenem and tazocine were the most effective in the management of such infections. The most frequent genotype of ESBL was OXA (19.2 %) for E. coli and SHV (92.5 %) for Klebsiella spp. The highest genotypic combination found was the combination of TEM/OXA (44.2 %) for E. coli.

Conclusion: The resistance of E. coli and Klebsiella spp-producing ESBLs in Pakistan is a serious issue, and TEM, OXA and SHV type ESBL were the most common genotypes. Some isolates produced two or three genotypes at a time. Multiplex PCR of ESBL may help in early detection as well as phenotypic antibiotic therapy of these infections.

Keywords: Beta-lactamases, Escherichia coli, Klebsiella spp, Antibiotic susceptibility, Plasmid-encoded, Structural genes, Imipemem, Meropenem, Tazocine