Prevalence of Extended-Spectrum Beta-Lactamases Enzymes in Enterobacter Aerogenes Isolated from Urinary Tract Infections in Shahrekord City

Abstract

Introduction: Enterobacteriaceae produce the Extended-Spectrum Beta-Lactamases which is considered as an important resistant mechanism of beta-lactam antibiotics. The resistance to beta-lactam antibiotics is the main problem in the bacterial infections therapy. The prevalence of these enzymes changes in different geographical areas and with time. The present study aims to explore the frequency of the extended-spectrum blaSHV, blaCTX-M, blaTEM, in Enterobacter aerogenes isolated from urinary tract infections in Shahrekord City; the mentioned genes were investigated from the phenotypic and genotypic point of view.
 Methods: In this cross-sectional descriptive study, antibacterial susceptibility patterns of 50 isolates of Enterobacter aerogenes to Cefotaxim, Ceftazidim, Cefterixon and cephalotin were tested using disk diffusion (Kirby-Buer) method. In addition, confirmatory tests for detecting ESBLs phenotypes were performed using Ceftazidim-clavulanic acid and Cefotaxim- clavulanic acid combination disks. Then, the presence of blaSHV, blaCTX-M, blaTEM, genes in the broad-spectrum beta-lactamase producing strains was assessed in the presence of specific primers.
 Results: Out of 50 isolates of Enterobacter aerogenesis investigated in this study, 32 isolates (64%) were identified to produce broad-spectrum β-lactamases in the phenotypic study of ESBLS, and the prevalence of blaCTX-M, blaTEM and blaSHV was reported as 30%, 20% and 14%, respectively. In the statistical analysis, a statistically significant correlation was observed between resistance to the antibiotic ceftriaxone and the blaCTX-M, gene (p<0.05).
 Conclusion: The present study suggests that ESBL producing Enterobacter aerogenes isolates have a high prevalence. The increase in the number of these species is often caused due to the irrational prescription of antibiotics, which requires the use of new antimicrobial agents and limiting the unnecessary use of antimicrobial agents and increasing the use of infection control tools.