RESUMO
Seventy Escherichia coli isolates recovered from diseasedchickens diagnosed with colibacillosis in Henan Province,China, between 2004 and 2005 were characterized forantimicrobial susceptibility profiles via a broth doublingdilution method. Overall, the isolates displayed resistanceto trimethoprim-sulfamethoxazole (100%), oxytetracycline(100%), ampicillin (83%), enrofloxacin (83%), and ciprofloxacin(81%), respectively. Among the phenicols, resistance wasapproximately 79% and 29% for chloramphenicol andflorfenicol, respectively. Molecular detection revealed thatthe incidence rates of the floR, cmlA, cat1, cat2 and cat3were 29, 31, 16, 13, and 0%, respectively. Additionally,10% of the isolates were positive for both floR and cmlA.As these antimicrobial agents may potentially inducecross-resistance between animal and human bacterialpathogens, their prudent use in veterinary medicine ishighly recommended.