qepA gene detection among archived Quinolone resistant uropathogenic Escherichia coli isolates obtained from Microbiology Laboratory, Makerere University, Uganda.

Abstract

World over, plasmid-mediated quinolone resistance in Escherichia coli clinical isolates is a serious challenge. This is worsened by non-robust surveillance and a scarcity of databases about region-specific determinants of antimicrobial resistance. This information would help in revising antimicrobial therapy in these regions. This study was aimed at the detection of qepA-gene-mediated quinolone-resistance among archived uropathogenic Escherichia coli isolates obtained from the Clinical Microbiology Laboratory, Makerere University College of Health Sciences, Kampala, Uganda. 30 known quinolone-resistant E. coli isolates collected from 2017 to 2020 were retrieved. Phenotypic and Biochemical tests were performed to confirm E. coli. Disk diffusion susceptibility test was done using Nalidixic acid (30µg) and Ciprofloxacin (5µg) to re-determine quinolone resistance. DNA was extracted from the isolates using the conventional CTAB method. A conventional PCR method was applied to amplify the qepA gene and Agarose Gel electrophoresis was used to visualize amplification of the PCR products. Of the 30 E. coli isolates retrieved, only 21 were eligible for the study. Only one isolate [E. coli (BT005)] was positive for the qepA gene. A very high number of isolates were resistant to Nalidixic acid and Ciprofloxacin, 95.24% (n=20) and 66.67% (n=14) respectively. 61.9% (n=13) were resistant to both quinolones. 23.8% (n=5) were susceptible to Ciprofloxacin and none (0%) were susceptible to Nalidixic acid. 9.52% (n=2) and 4.76% (n=1) displayed intermediate resistance to Ciprofloxacin and Nalidixic acid respectively. In Conclusion, Only one isolate out of 21 (4.76%) was positive for qepA gene confirming that qepA is still a rare determinant of quinolone resistance. 95% of the quinolone resistance observed in the Disk diffusion tests (ASTs) highlighted the role of other determinants of quinolone resistance other than qepA.