Prevalence of CTX-M genes in Escherichia coli strains in outpatient and inpatient cases with urinary tract infections in Isfahan, Iran

Abstract

Background: Extended-spectrum beta-lactamase of CTX-M-type is considered as an important mechanism resistant to beta-lactam drugs in the gram-negative pathogens. In this study, the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) as well as the frequency of CTX-M genes from urinary tract infections in inpatients and outpatients caused by Escherichia coli in selected health centers in Isfahan, Iran, was studied in 2013. Methods: The study was carried out on 120 E. coli isolates from inpatients and outpatients with urinary tract infection. The susceptibility of isolates was tested using disc diffusion method. The ESBL-producer strains were confirmed using combined discs method. Finally, the blaCTX-M gene was determined in ESBL-producer isolates using polymerase chain reaction (PCR) method. To identify the strains of E. coli producing CTX-M genes, PCR method was used. The collected data were entered and analyzed in WHONET 5.6 and Excel softwares. Findings: From 120 strains of E. coli, 12 outpatient (20.0) and 33 inpatient (55.0) isolates were ESBL-producer. 84.4 and 60.1 of outpatient isolates and 94.9 and 84.8 of inpatient isolates showed resistance to ampicillin and co-trimoxazole, respectively. PCR analysis revealed that 30 isolates had CTX-M gene. Conclusion: The production of ESBL, in particular in isolates of inpatients, is a big threat for use of the broadspectrum cephalosporins. Given the presence of CTX-M gene in the high proportion of the isolates, more molecular and epidemiological studies on pathogenic bacteria in health centers is required to be able to have a common plan to control bacterial resistance. © 2016, Isfahan University of Medical Sciences(IUMS). All rights reserved.