CTX-M gene and presence of insertion elements in patients with septicemia caused by Escherichia coli

Abstract

Introduction: Septicemia is a significant infection caused by some agents such as Escherichia coli. The goal of this study was to see how effective antibiotics were against E. coli isolates from septicemia patients, as well as to look into their genetic relationship. Materials and Methods: A total of 100 E. coli isolates were collected from septicemic patients. The antibiotic susceptibility testing was conducted with disk diffusion method. The prevalence of CTX-M gene and presence of insertion elements IS26 (IS26a and IS26b) and ISEcp1 were investigated. Phylogrouping, serogrouping and virulence typing were also investigated. The pulsed-field gel electrophoresis (PFGE) was also performed for genetic classification. Results: Fifty-one CTX-M positive isolates were identified. There was no resistance to phosphomycin. The ISEcp1, IS26a, and IS26b were detected in upstream of 84.3%, 5.8% and 9.8% of CTX-M, respectively. The orf477 was detected downstream of all CTX-M positive isolates. Thirty-six isolates belonged to the B2 phylogroup, followed by 25 D, 22 A, and 17 B1. The most frequent serogroup in the isolates is O1 serogroup. The highest rate of virulence genes included csgA, traT, iutA, hlyA, and kpsMII. The results of PFGE showed five clusters (A–E) using 80% cut-off. Conclusion: A significant relation between CTX-M gene and virulence factors was determined. Hence, surveillance and proper control strategies are essential to prevent the distribution virulent and drug-resistant E. coli. Although phosphomycin was found to be effective in eradicating extended spectrum β-lactamases-producing E. coli infections in septicemic patients, no genetic relationships between isolates were discovered.