Molecular Investigation and Confirmation of Clinical Isolates of Escherichia coli Urinary Infections and Evaluation of Frequency of qnrA Quinolone Resistance Gene by PCR Method

Background and Objective: Escherichia coli is responsible for 80-90% of urinary infections in outpatients and 30-50% of urinary infections in inpatients. The selection of inappropriate antibiotics for treatment has led to an increase in antibiotic resistance in E. coli isolates over the past few decades. The aim of this study was the phonotypical and molecular investigation of E. coli strains isolated from urinary tract infections and study the pattern of antibiotic resistance. We also evaluated the frequency of antibiotic resistance genes of qnrA in relation to quinolone resistance genes. Materials and Methods: In this cross-sectional study, 100 E. coli strains isolated from urinary tract infections of patients admitted to Sina Hospital in Hamadan City were collected and studied by phenotypically and molecular methods. An antibiotic resistance pattern was determined using the disk diffusion method, and specific primers for the qnrA antibiotic resistance gene were evaluated using the polymerase chain reaction method. Results: Finally, among 100 confirmed E. coli isolates, 70% of the strains were resistant to nalidixic acid, 53% to levofloxacin, and 59% to ciprofloxacin. The frequency of the qnrA resistance gene was 28%. Conclusion: The present study showed the high resistance of E. coli to quinolones. The presence of the qnrA gene can be one of the factors contributing to this resistance