Description of extraintestinal pathogenic Escherichia coli based on phylogenetic grouping, virulence factors, and antimicrobial susceptibility

Background and Objectives: Extraintestinal pathogenic Escherichia coli (ExPEC) is a recently recognized and highly diverse pathotype of E. coli. Its significance as a pathogen has increased due to the emergence of hypervirulent and multidrug-resistant (MDR) strains. The aim of this study was to characterize ExPEC isolates from humans based on their phylogenetic group, virulence factor profile, and antimicrobial susceptibility. Materials and Methods: The isolates were collected from patients with extraintestinal infections caused by E. coli, including urinary tract infections, bacteremia, and surgical site infections. The E. coli phylogenetic groups were determined using multiplex PCR. Additionally, the isolates were evaluated for their biofilm-forming abilities, susceptibility to antimicrobial agents, and presence of virulence genes. Results: In this study, the isolates were classified into four phylogenetic groups: A (48.3%), B2 (25.8%), D (19.35%), and B1 (6.45%). All isolates exhibited at least one of the ten analyzed virulence factors. However, there was no direct evidence linking a specific phylogenetic group to a particular virulence factor. Nevertheless, the presence of the fimH, fyuA, ompT, traT, and kpsMTII virulence genes was correlated with the production of strong biofilms, multidrug resistance (MDR), and the production of alpha hemolysin. Conclusion: This study provides a description of the phylogenetic groups in ExPEC and their potential association with virulence factor profiles and antimicrobial susceptibility.