This study was carried out to investigate the antimicrobial resistance pattern and distribution of resistance gene determinants in fecal E. coli from chicken. Antimicrobial susceptibility test was performed on a total of 109 fecal E. coli isolates from chicken, collected in Gyeonggi, Chungbuk, Jeonnam and Jeonbuk province from March to November 2003, by the disk agar diffusion method. Eighteen commonly used antimicrobial agents approved in Korea as veterinary medicine were tested: ampicillin (AM), amoxicillin/clavulanic acid (AMC), cephalothin (CF), cefozolin (CZ), cefoxitin (FOX), cefotaxime (CTX), cefepime (FEP), imipenem (IPM), streptomycin (S), gentamicin (GM), amikacin (AN), ciprofloxacin (CIP), enrofloxacin (ENO), norfloxacin (NOR), trimethoprim/sulfamethoxazole (SXT), erythromycin (E), chloramphenicol (C) and tetracycline (TE). Higher resistance rates (≥50%) were observed against 9 antimicrobial agents including AM, CF, S, CIP, ENO, NOR, SXT, E and TE. Resistance was most frequent for TE in 105 E. coli isolates (96.3%). Twenty-two isolates (20.2%) of the isolates showed multiple antimicrobial resistance to 8, and 19 isolates (17.4%) showed to 7 antimicrobial agents. The distribution of the resistance gene determinants for S and TE was assessed by PCR in resistant isolates. Thirty isolates possessed the strA, strB, and aadA gene, 25 isolates possessed the strA and strB gene among the 66 streptomycin-resistant isolates. Fifty one isolates possessed only the tetA gene, 22 isolates possessed the tetA and tetB gene, 11 isolates possessed only the tetB gene among the tetracycline-resistant isolates.

ABSTRACT
 서 론
 재료 및 방법
  1. 대상 농장 및 공시 재료
  2. 균 분리 및 동정
  3. 항생제 내성 시험
  4. DNA 추출
  5. Oligonucleotide primer 합성 및 PCR
  6. 전기영동
 결 과
 고 찰
 참고문헌

• 채명주(경북대학교 수의과대학) | Myeong Ju Chae (College of Veterinary Medicine, Kyungpook National University)
• 이영주(경북대학교 수의과대학) | Young Ju Lee (College of Veterinary Medicine, Kyungpook National University) Correspondence