Phenotypic and Genotypic Study of Antibiotic Resistance among Escherichia coli Isolates from Human Urinary Infection Cases in Bojnord Province

Background and Objective: Bacterial agents are the most common causes of urinary infection with Escherichia coli as the major causative organism. Accordingly, the current study aimed to determine the antibiotic resistance among Escherichia coli isolates from human urinary infection cases. Materials and Methods: The current experimental study was carried out on 50 specimens of positive cultures with urinary tract infection referred to Imam Reza Hospital Laboratory in Bojnord, Iran. The resistance and susceptibility of the isolates were assessed using disc diffusion method. Moreover, the presence of tetA, blaTEM, Sul1, aac(3)-IV, and aadA1 gens was examined using molecular methods with specific primers. Results: Prevalence of antibiotic resistance to ampicillin, cotrimaxazole, levofloxacin, nalidixic acid, ciprofloxacin, gentamicin, and nitrofurantoin was measured at 84%, 60%, 60%,52%, 44%, 22%, and 6%, respectively. in total, 50 E. coli strains were isolated were examined to determine blaTEM, aac(3)-IV, tetA, Sul, and aadA1 genes using polymerase chain reaction(PCR). Based on the obtained results, the frequency of blaTEM, aac(3)-IV, tetA, Sul1, aac(3)-IV, and aadA1 genes was reported as 24%, 12%,10%, 8%, and 14%, respectively. Conclusion: Disk diffusion agar method can be used as a primary screening method to determine antibiotic susceptibility for Escherichia coli isolates separated from urinary tract infections. In addition, genotypic method can be implemented for the accurate evaluation of the resistance of the isolates.