Antimicrobial resistance and virulence determinants of E. coli isolated from companion animals: A potential public health concern

Abstract

Antimicrobial resistance (AMR) in Escherichia coli, particularly extended-spectrum beta-lactamase (ESBL) and carbapenemase-producing strains, poses a significant zoonotic risk. This study investigates the prevalence of AMR and virulence determinants in E. coli isolated from dogs and cats in Egypt. A total of 102 rectal swabs were analyzed, with E. coli recovered from 55 (53.9 %) samples, more frequently in cats (19/30; 63.3 %) than in dogs (36/72; 50 %). ESBL-producing isolates were detected in both healthy (5/28; 17.9 %) and diseased (6/27; 22.2 %) animals. The most common resistance genes were blaTEM and blaCTX-M, often occurring with blaCMY-2. Although phenotypic carbapenem resistance was uncommon (5.45 %), carbapenemase-encoding genes were identified in 60 % of isolates, suggesting a potential but unconfirmed reservoir of resistance. Virulence gene profiling revealed that most isolates carry virulence genes primarily associated with extra-intestinal pathogenic E. coli (ExPEC), followed by enterohemorrhagic E. coli (EHEC), with both detected in diseased and asymptomatic animals. Cluster analysis demonstrated strong associations between AMR and virulence determinants, underscoring the convergence of resistance and pathogenic potential. These findings highlight the coexistence of resistance and virulence genes in companion animal E. coli, and reinforce the need for prudent antimicrobial use and One Health-based surveillance to limit the emergence and dissemination of AMR.