The phenotypic and genotypic evaluation of resistance to quinolone antibiotics in clinical Escherichia coli isolated from urinary tract infection of hospitalized patients in Tehran, Iran in 2017

Antibiotic resistance to quinolones as a therapeutic agent of urinary tract infection in increasing in the world. Thus, this study was designed to evaluate the resistance to quinolone antibiotics in Escherichia coli isolated from urinary tract infection of hospitalized patients in Tehran, Iran in 2017.
In the present study, 150 E. coli isolates was collected from urine of hospitalized patients with urinary tract infection in Tehran, Iran. Evaluation of resistance to quinolone antibiotics was done by disk diffusion method. After genome extraction with phenol l& chloroform method, amplification of qnrA, qnrB and qnrS genes in the isolates was performed by PCR.
The rate of resistance to antibiotics nalidixic acid, ciprofloxacin, norfloxacin and levofloxacin in these isolates was 76%, 48%, 30%, and 18%. The results of amplification the qnr genes showed that 40% of isolates harbored at least one of the qnrA, qnrB and qnrS genes. Among the 60 isolates harboring the qnr genes, 73.3%, 23.3% and 3.4% had qnrS, qnrB and qnrA genes, respectively. Statistical analysis of results showed that there was a significant relation between the co-presence of qnrS and qnrB with co-resistance to nalidixic acid and ciprofloxacin antibiotics
In this study, a significant rate of resistance to quinolone antibiotics was observed in E. coli isolated from patients with urinary tract infection in Tehran hospitals that showed a remarkable rate of resistant genes. It is suggested to study the origin of these infections in the collected samples in the future.