Characterization of antimicrobial susceptibility, extended-spectrum β-lactamase genes and phylogenetic groups of enteropathogenic Escherichia coli isolated from patients with diarrhea

Abstract

Objectives: Infectious diarrhea is one of the most common causes of pediatric death worldwide and enteropathogenic Escherichia coli (EPEC) is one of the main causes. There are 2 subgroups of EPEC, typical and atypical, based on the presence or absence of bundle forming pili (bfp), of which atypical EPEC is considered less virulent, but not less pathogenic. Antimicrobial resistance towards atypical EPEC among children is growing and is considered a major problem. In this study the pattern of antibiotic resistance in clinical isolates was determined. Methods: Using 130 isolates, antibiotic resistance patterns and phenotypes were assessed, and genotypic profiles of extended spectrum β-lactamase (ESBL) production using disc diffusion and PCR was carried out. Phylogenetic groups were analyzed using quadruplex PCR. Results: There were 65 E. coli isolates identified as atypical EPEC by PCR, among which the highest antibiotic resistance was towards ampicillin, followed by trimethoprim-sulfamethoxazole, and tetracycline. Multidrug resistance was detected in 44.6% of atypical EPEC isolates. Around 33% of isolates were determined to be extended spectrum β-lactamase producers, and in 90% of isolates, genes responsible for ESBL production could be detected. Moreover, the majority of atypical EPEC strains belonged to Group E, followed by Groups B1, B2 and C. Conclusion: High rates of multidrug resistance and ESBL production among atypical EPEC isolates warrant periodical surveillance studies to select effective antibiotic treatment for patients. It is considered a critical step to manage antibiotic resistance by avoiding unnecessary prescriptions for antibiotics.