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
and Fatih Mehmet Keleşoğlu3
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:
E-mail:
hasannazik01@gmail.com
Tel:
+902124142000/32810, +905336946090
Received: 5 October
2010 Revised
accepted: 16 April 2011
Tropical
Journal of Pharmaceutical Research, June 2011;
10(3):
325-333
doi:
10.4314/tjpr.v10i3.9
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 blaCTX-M-15
gene, while qnrA1 occurred with blaTEM-1, blaSHV,
and blaVEB-1 genes. 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 betalactamase (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 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.
Keywords:
β-lactamase, Quinolone resistance, aac(6)-Ib-cr,
CTX-M-15, VEB-1
