Abstract: Total of 34 chicken rectal swab samples were collected to isolate and identify Escherichia coli. And all isolates were tested for susceptibility to 8 antimicrobial agents by using the broth micro-dilution method. As a result, 34 intestinal Escherichia coli isolates recovered from chicken were identified and 4 of them were hydrogen sulfide producing stains. Their MIC₅₀ to kanamycin, chloramphenicol, ampicillin, cyprofloxacin, ceftriaxone sodium, gentamicin, sulfadiazine and doxycycline were more than 256 μg/mL, equal to 256 μg/mL, more than 256 μg/mL, equal to 16 μg/mL, less than 0.125 μg/mL, equal to 256 μg/mL, more than 512 μg/mL and equal to 16 μg/mL,respectively. And their resistant rates to these 8 antimicrobial agents were ordered as 100.0%, 100.0%, 100.0%, 70.6%, 11.8%, 94.1%, 100.0% and 82.3%, respectively. All isolates were multi-drug resistant strains. The minimal and maximum kinds of antimicrobial agents to 34 Escherichia coli strains were 5 and 8, respectively. The percentages of resistant isolates against 5, 6, 7 and 8 antimicrobial agents were ordered as 5.9%, 32.4%, 58.8% and 2.9%.It was suggested that wide resistant spectrum and high resistant ratio were presented in 34 intestinal Escherichia coli isolates. Medicinal proposals in clinical should be adjusted according to the antimicrobial susceptibility test.

Key words: chicken; hydrogen sulfide producing Escherichia coli; identification; resistance