Plasmid-Mediated Quinolone-Resistance (qnr) Genes in Clinical Isolates ofEscherichia coliCollected from Several Hospitals of Qazvin and Zanjan Provinces, Iran.
OBJECTIVE
Escherichia coliis regarded as the most important etiological agent of urinary tract infections. Fluoroquinolones are routinely used in the treatment of these infections; however, in recent years, a growing rate of resistance to these drugs has been reported globally. The aims of this study were to detect plasmid-mediatedqnrA,qnrB, andqnrSgenes among the quinolone-nonsusceptibleE. coliisolates and to investigate their clonal relatedness in Qazvin and Zanjan Provinces, Iran.


METHODS
A total of 200 clinical isolates ofE. coliwere collected from hospitalized patients. The bacterial isolates were identified through standard laboratory protocols and further confirmed using API 20E test strips. Antimicrobial susceptibility was determined by the standard disk diffusion method. Polymerase chain reaction (PCR) and sequencing were used for detectingqnrA,qnrB, andqnrSgenes and the clonal relatedness ofqnr-positive isolates was evaluated by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) method.


RESULTS
In total, 136 (68%) isolates were nonsusceptible to quinolone compounds, among which 45 (33.1%) and 71 (52.2%) isolates showed high- and low-level quinolone resistance, respectively. Of the 136 isolates, four (2.9%) isolates were positive for theqnrS1gene. The results from ERIC-PCR revealed that two (50%) cases ofqnr-positive isolates were related genetically.


CONCLUSIONS
Our study results were indicative of the presence of low frequency ofqnrgenes among the clinical isolates ofE. coliin Qazvin and Zanjan Provinces, which emphasizes the need for establishing tactful policies associated with infection-control measures in our hospital settings.
Department of Microbiology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
Maryam
M
Rezazadeh
Department of Microbiology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
Hamid
H
Baghchesaraei
Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.
Amir
A
Peymani
Escherichia coli; enterobacterial repetitive intergenic consensus-polymerase chain reaction; qnr genes