Antimicrobial patterns of Avian Pathogenic Escherichia coli isolated from broiler chickens

E. coli infections in avian species are an economic threat to the poultry industry worldwide. The spread of MDR bacteria has been recognized as an increasing problem in the veterinary and medical fields. The current study aimed to investigate the phenotypic and genotypic antimicrobial patterns of avian Pathogenic E. coli isolated from broiler chickens. Results of in-vitro antimicrobial susceptibility testing showed that E. coli isolates were more sensitive to imipenem only (72.4%). On the other hand, they were highly resistant to most of used antimicrobials including ciprofloxacin (95.9%), amikacin (94.9%), cefotaxime sodium (92.9%), gentamicin (89.9%), cefotriaxone (89.9%), topramycin (87.8%), sulphamethoxazole/trimethoprime (85.7%), ceftazidim (84.7%). Also, they were resistant to cefoprazone (79.9%), doxycycline (72.4%) and amoxycillin/clavulinic acid (69.4%). All the tested isolates of E. coli (100%) were multi drug resistant (MDR). PCR was applied on 15 MDR E. coli isolates to determine 4 genes responsible for antibiotic resistance included ampC, blaCTX, blaSHV and tetA (A). The results revealed that that ampC and blaCTX genes were the most prevalent found in all isolates (100%) while tetA (A) and blaSHV genes were harbored in 14 isolates (93.3%).