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 beta-lactamases
By:Nazik, H (Nazik, Hasan)[ 1 ] ; Bektore, B (Bektore, Bayhan)[ 2 ] ; Ongen, B (Ongen, Betigul)[ 1 ] ; Ilktac, M (Ilktac, Mehmet)[ 1 ] ; Ozyurt, M (Ozyurt, Mustafa)[ 2 ] ; Kuvat, N (Kuvat, Nuray)[ 1 ] ; Baylan, O (Baylan, Orhan)[ 2 ] ; Kekulluoglu, H(Kekulluoglu, Hatun)[ 1 ] ; Haznedaroglu, T (Haznedaroglu, Tuncer)[ 2 ] ; Kelesoglu, FM (Kelesoglu, Fatih Mehmet)[ 3 ]
TROPICAL JOURNAL OF PHARMACEUTICAL RESEARCH
Published: JUN 2011
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Purpose: To evaluate the occurrence of plasmid-mediated quinolone resistance (PMQR) genes and the prevalence of extended spectrum beta-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 beta-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-15) gene, while qnrA1 occurred with bla(TEM-1), bla(SHV), and bla(VEB-1) genes. The most frequent beta-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 beta-lactamase was detected in ESBL-producing E. coli strains. This study also identified the co-expression of qnrA1 and blaVEB-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.