Detection of qnr genes in ESBLs producing and non-producing coliforms


Background and objectives: The discovery of plasmid-mediated quinolone resistance (PMQR) in the late 1990's added a new dimension to quinolone resistance. During the last years, the occurrence of extended-spectrum-β-lactameses (ESBLs) and (PMQR) within coliforms group has gained particular attention. The objective of this study was to determine the prevalence of plasmid-mediated fluoroquinolone resistance genes in ESBL-producing coliformsMaterials and method: One hundred and seventy three clinical samples collected from both gender , (110) from urinary tract infections ( UTIs ), and (63) from patients with diabetic foot infections ( DFIs ) who visited or admitted to AL- Salam General Teaching Hospital and AL- Wafa‘a center for diabetic patients in Mosul city of Ninavah province / Iraq from April 2013 to February 2014.The isolates were identified to species level depended on morphological, biochemical and physiological tests and confirmed by RapIDTM ONE system (Remel USA).Results: The results showed the majority of them were resistant to most antibiotics. Resistance was observed most often to nalidixic acid (85.9%)followed by norfloxacin (70.5%) and ciprofloxacin (67%). All ciprofloxacin resistant isolates were tested for their ability to produce the extended spectrum β-lactamase (ESBL) enzymes using the double disk synergy test (DDST). Out of the total (57) ciprofloxacin resistant coliforms tested, (66.7%) were ESBL producers. Ciprofloxacin resistant coliforms species were conducted for PCR to investigate the presence of qnr genes. Out of (57) ciprofloxacin resistant spp. qnrB gene (469 bp) was detected in 14(24.6%) spp. while none of the species had qnrA and qnrS genes in our study. The results also revealed that qnrB gene was found in all (100%) of ESBL-producing E. coli and K. pneumoniae spp.Keywords: Ciprofloxacin resistance, qnr genes, Coliforms