Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli Urinary Isolates from Two Teaching Hospitals in Turkey: Coexistence of TEM, SHV, CTX-M and VEB-1 Type β-lactamases

Hasan Nazik¹ , Bayhan Bektöre², Betigül Öngen¹, Mehmet İlktaç¹, Mustafa Özyurt², Nuray Kuvat¹, Orhan Baylan², Hatun Keküllüoğlu¹, Tunçer Haznedaroğlu², Fatih Mehmet Kelesoğlu³

¹Istanbul Medical Faculty, Department of Microbiology and Clinical Microbiology; ²Gulhane Military Medical Academy, Haydarpasa Training Hospital, Department of Medical Microbiology; ³Istanbul University, Istanbul Medical Faculty, Department of Pediatrics, Istanbul, Turkey.

For correspondence:- Hasan Nazik Email: hasannazik01@gmail.com Tel:+902124142000/32810

Received: 5 October 2010 Accepted: 16 April 2011 Published: 24 June 2011

Citation: Nazik H, Bektöre B, Öngen B, İlktaç M, Özyurt M, Kuvat N, et al. Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli Urinary Isolates from Two Teaching Hospitals in Turkey: Coexistence of TEM, SHV, CTX-M and VEB-1 Type β-lactamases. Trop J Pharm Res 2011; 10(3):325-333 doi: 10.4314/tjpr.v10i3.9

© 2011 The authors.
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Abstract

Purpose: To evaluate the occurrence of plasmid-mediated quinolone resistance (PMQR) genes and the prevalence of extended spectrum β-lactamase (ESBL) types in Escherichia coli clinical isolates.

Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed using the disc diffusion method. ESBL production was determined using a double-disc synergy test for all isolates; E-test and Vitek 2 were used for plasmid-mediated quinolone resistance (PMQR)-positive isolates and their transconjugants. The presence of PMQR and β-lactamase genes was determined by polymerase chain reaction (PCR).

Results: The strains displayed high rates of resistance to norfloxacin (80 %). The most frequent PMQR gene was aac(6’)-Ib-cr (45.9 %). In all, one qnrA1 (1.6 %), one qnrS1 (1.6 %), and two qepA1-positive isolates (5.7 %) were identified. The genes, qnrS1+aac(6’)-Ib-cr and qepA1, were co-expressed with bla_CTX-M-15gene, while qnrA1 occurred with bla_TEM-1, bla_SHV, and bla_VEB-1genes. The most frequent β-lactamase type was cefotaximase (CTX-M), which generally hydrolyzes cefotaxime (92 %) more than it does ceftazidime; followed by temoneira (TEM, 39 %); sulfhydryl variable (SHV, 5 %), and Vietnamese extended-spectrum beta–lactamase (VEB, 1.6 %).

Conclusion: A high prevalence of aac(6’)-Ib-cr and CTX-M type β-lactamase was detected in ESBL-producing E. coli strains. This study also identified the co-expression of qnrA1 and bla_VEB-1 genes and of qnrS1+aac(6’)-Ib-cr in E. coli isolates. The co-existence of PMQR genes with ESBLs may lead to a serious public health problem.

Keywords: ^6;-lactamase, Quinolone resistance, aac(6â€™)-Ib-cr, CTX-M-15, VEB-1