فهرست نشریات علمی دسترسی آزاد ایران

Avian pathogenic Escherichia coli (APEC) represents a major threat to poultry production and public health due to its high virulence potential and the rising prevalence of antimicrobial resistance. This study investigated the prevalence of antimicrobial resistance and virulence genes among E. coli isolates recovered from broiler chickens in the West Azerbaijan Province of Iran. A total of 120 isolates obtained from blood and liver samples were identified using standard bacteriological methods and confirmed by PCR amplification targeting the 16SrRNA gene. The presence of fluoroquinolone resistance genes (qnrS and qnrB) and the adhesion‑associated virulence gene fimA was assessed. Isolates were analyzed according to bird age, season, and geographic region. All isolates (100%) were positive for the 16SrRNA gene. The overall prevalence of qnrS and qnrB was 47.56% for each gene, while fimA was detected in 29.27% of the isolates. The highest prevalence of qnrS (52.63%) and fimA (31.58%) occurred in 10‑day‑old chicks, with a marked decline in fimA expression at 30 days of age. Regionally, qnrB was significantly more prevalent in the southern region (79.17%) compared with the central (23.81%) and northern (40.54%) regions. Seasonal analysis showed higher detection rates of qnrS and fimA during winter. The co‑occurrence of fluoroquinolone resistance and virulence genes in APEC highlights a critical One Health concern, as these resistance determinants could potentially disseminate to human extraintestinal pathogenic E. coli. Continuous molecular surveillance and prudent antimicrobial usage are strongly recommended.