A comparative study of the prevalence of extended-spectrum β-lactamaseproducing Escherichia coli among urinary and fecal Escherichia coli isolates of women with urinary tract infection in Kerman city

Background & Aim: Important challenge for treatment of urinary tract infections is the spread of extended-spectrum beta-lactamases (ESBLs) producing Escherichia coli. Therefore, the frequencies of main beta-lactamase genes, resistance to beta-lactams and the ability of ESBLs production in urinary and fecal Escherichia coli of women with urinary tract infections were compared. Methods: In 60 Escherichia coli isolates, including 30 isolates from urine and 30 isolates from stool of 30 women with urinary tract infections, the presence of blaCTX-M and blaTEM genes was investigated using polymerase chain reaction, resistance to ceftazidime, cefotaxime and ceftriaxone was investigated by the disk diffusion technique and the frequency of ESBLs producing isolates was investigated by the phenotypic confirmation method of the Clinical and Laboratory Standard Institute. Results: The frequencies of blaCTX-M and blaTEM in fecal isolates were 73.3% and 86.7%, and in urinary isolates were 83.3% and 90%, respectively. Resistance to ceftazidime, cefotaxime and ceftriaxone was equally observed in 10% of fecal isolates and 23.3%, 20% and 20% of urinary isolates, and 3.3% of fecal isolates and 13.3% of urinary isolates were ESBLs producers. These frequencies were not significantly different between fecal and urinary isolates. The noticeable similarities of the studied characteristics among the fecal and urinary isolates of each woman strengthen the possibility of existence of genetic similarity between urinary infection agents and intestinal flora or transmission of mobile genetic elements between them. Conclusion: Performing the antimicrobial susceptibility tests on clinical samples is necessary to select the most effective drug and reduce treatment costs.