Prevalence of blaCTX-M1, blaCTX-M14 and blaCTX-M15 Genes among Escherichia ColiIsolated from Urinary Tract Infections in Outpatients, Kermanshah City, Iran

Background and Aims: The rate of urinary tract infection caused by the extended-spectrum-β-lactamase- (ESBL) producing Escherichia coli (E. coli) is increasing worldwide. This study aimed to assess the frequency of blaCTX-M genes in the E. coli isolated from urinary tract infection (UTI) in outpatients. Methods: 240 E. coli bacteria were isolated from the outpatients’ urine samples in the Kermanshah city, Iran. The susceptibility of isolates to 10 selected antibiotics was tested using the disc diffusion method. Then, the phenotype of the extended-spectrum-β-lactamase-producing isolates was determined using the combined disc method. Finally, blaCTX-M1, blaCTX-M14 and blaCTX-M15 genes were determined via polymerase chain reaction (PCR) method. Results: Of 240 isolates, 199 isolates (82.9%) showed resistance to ampicillin, but 100% were sensitive to imipenem. 96 isolates (40.0%) were resistant to three or more antibiotic groups. Moreover, 67 isolates (27.9%) were extended-spectrum-β-lactamase producer and 61 (91.0%), 58 (86.6%) and 21 (31.3%) isolates contained blaCTX-M1, blaCTX-M14 and blaCTX-M15 genes, respectively. Conclusion: Resistance to various β-lactam antibiotics, in particular the third generation of cephalosporins, among community-acquired E. coli isolates is a serious concern in Kermanshah city. Production of extended-spectrum β-lactamase, specially the dissemination of blaCTX-M genes among communityacquired E. coli isolates, is a big threat for using expected-spectrum cephalosporins. Given the presence of extended-spectrum-β-lactamase genes in the high proportion of the urinary tract infection isolates, suitable antibiotics should be chosen according to the antibiotic susceptibility tests.