Phenotypic and Genotypic Antimicrobial Resistance Patterns of Escherichia coli in Companion Dogs and Their Owners from Southeast Iran: A One Health Approach

Background: Antimicrobial resistance (AMR) represents a critical global health issue within the One Health framework. Companion animals, particularly dogs, may act as reservoirs for resistant bacteria, facilitating their transmission to humans. This study aimed to investigate the phenotypic and genotypic antimicrobial resistance patterns of Escherichia coli isolated from companion dogs, their owners and a human control group without pet contact. Methods: A total of ۱۳۵ fecal samples were collected from ۴۵ dogs, ۴۵ owners, and ۴۵ non-owners. Isolates were identified as Escherichia coli using standard biochemical tests. Antimicrobial susceptibility testing against ۱۱ antibiotics was performed via the disk diffusion method. Genotypic detection of resistance genes for beta-lactams (blaTEM, blaSHV, blaOXA, blaCTX-M), tetracyclines (tetA, tetB), sulfonamides (sulI, sulII), trimethoprim (dhfrI, dhfrV), aminoglycosides (aadA۱, strA, strB) and quinolones (qnrA, qnrB) was conducted by PCR. Statistical analysis was performed using Chi-square and Fisher’s exact tests. Results: All fecal samples yielded Escherichia coli isolates. Phenotypically, the highest resistance rate was observed for erythromycin in all groups (۸۸.۸–۱۰۰%). Genotypically, the most prevalent genes were blaCTX-M and sul۱ in dogs, tetA in owners, and blaTEM in the control group. Resistance was significantly associated with breed, living environment and antibiotic use in dogs, and with gastrointestinal infection history in owners (p ≤ ۰.۰۵). No significant associations were found with diet or hand hygiene. Conclusion: The findings demonstrate the widespread occurrence of AMR Escherichia coli among dogs and their owners, with higher resistance levels in humans, suggesting possible human-to-animal transmission. These results highlight the necessity for rational antibiotic use and integrated One Health surveillance to mitigate AMR dissemination between companion animals and humans.

کلیدواژه ها:

Antimicrobial resistance ، Escherichia coli ، Companion dogs ، One Health ، Iran