Frequencies of tetracycline resistance genes (tetA, and tetB), and antimicrobial resistance profile of Escherichia coli isolated from broilers of West Azerbaijan province were investigated. Concerns have been raised regarding the emergence of antimicrobial resistance in pathogenic organisms and therapy failure in veterinary and human medicine. The resistance profile of 44 E. coli isolates recovered from colisepticaemic broilers to five commonly used antibiotics were investigated by disk diffusion method. Tetracycline resistance genes (tetA, and tetB) also were detected by PCR. The results showed that E. coli isolates had the highest resistance rate to tetracycline, sulfadiazine, and florfenicol. Of the isolates 54.5% (24/44) carried tetracycline resistance genes. The positive rates of tet(A) and tet(B) were 47.7% (21/44) and 9% (4/44), respectively. One E. coli isolate carried both tetracycline resistance genes. The finding of this study represented high frequency of resistance to antimicrobial agents used in Iranian poultry industry, especially to tetracycline.

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