Original Article

Korean J Lab Med 2009; 29(4): 293-298

Published online August 1, 2009

Copyright © Korean Society for Laboratory Medicine.

Resistance Trends of Bacteroides fragilis Group Over an 8-Year Period, 1997-2004, in Korea

Kyoung Ho Roh, M.D.1, Sinyoung Kim, M.D.2,3, Chang-Ki Kim, M.D.4, Jong Hwa Yum, Ph.D.5, Myung Sook Kim, M.T.2, Dongeun Yong, M.D.2,3, Kyungwon Lee, M.D.2,3, June Myung Kim, M.D.6, and Yunsop Chong, Ph.D.2

Department of Laboratory Medicine1, Korea University College of Medicine, Seoul; Department of Laboratory Medicine and Research Institute of Bacterial Resistance2, and Brain Korea 21 for Medical Sciences3, Yonsei University College of Medicine, Seoul; Korean Institute of Tuberculosis4, Seoul; Department of Clinical Laboratory Science5, Dongeui University, Busan; Department of Internal Medicine6, Yonsei University College of Medicine, Seoul, Korea

Correspondence to: Dongeun Yong, M.D.
Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea
Tel : +82-2-2228-2442 Fax : +82-2-313-0956
E-mail :

*This work was supported by the Brain Korea 21 Project in 2005.

Received: February 20, 2009; Revised: May 8, 2009; Accepted: May 21, 2009


Background : Bacteroides fragilis group organisms are the most frequently isolated anaerobes in human infections. Increasing resistance to various antimicrobial agents is a significant problem in choosing appropriate antimicrobial agents to treat anaerobic infections. Periodic monitoring of the regional resistance trends of B. fragilis group isolates is needed.
Methods : A total of 466 nonduplicate clinical isolates of B. fragilis group organisms (276 B. fragilis, 106 Bacteroides thetaiotaomicron, and 84 other B. fragilis group organisms) were collected during the 8-yr period from 1997 to 2004 in a Korean university hospital. Minimum inhibitory concentrations to various antimicrobial agents were determined by the CLSI agar dilution method.
Results : Eight isolates were resistant to imipenem. Additionally, the resistance rates to cefotetan were decreased in B. thetaiotaomicron, while those for clindamycin were significantly increased compared to the rates found in previous studies. Depending on species, resistance rates were 1-4% for imipenem, 1-6% for piperacillin-tazobactam, 4-11% for cefoxitin, 33-49% for piperacillin, 14-60% for cefotetan, and 51-76% for clindamycin. No isolates were resistant to chloramphenicol or metronidazole.
Conclusions : Piperacillin-tazobactam, cefoxitin, imipenem, chloramphenicol, and metronidazole are still active against B. fragilis group isolates, while clindamycin no longer has a value as an empirical therapeutic agent in Korea. Furthermore, this study identified the first imipenem-resistant B. fragilis group isolates in Korea.

Keywords: Bacteroides fragilis group, Antimicrobial susceptibility, Trend, Korea