Ann Lab Med 2019; 39(2): 190-199
Antimicrobial Susceptibility Patterns of Anaerobic Bacterial Clinical Isolates From 2014 to 2016, Including Recently Named or Renamed Species
Jung-Hyun Byun, M.D.1, Myungsook Kim, Ph.D.1, Yangsoon Lee, M.D.2, Kyungwon Lee, M.D.1, and Yunsop Chong, Ph.D.1
1Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea; 2Department of Laboratory Medicine, Hanyang University Seoul Hospital, Hanyang University College of Medicine, Seoul, Korea
Corresponding author: Yangsoon Lee, M.D.
Department of Laboratory Medicine, Hanyang University Seoul Hospital, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
Tel: +82-2-2290-9655
Fax: +82-2-2290-9193
Received: May 15, 2018; Revised: July 17, 2018; Accepted: October 25, 2018; Published online: March 1, 2019.
© Korean Society for Laboratory Medicine. All rights reserved.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background: Anaerobic bacterial resistance trends may vary across regions or institutions. Regional susceptibility patterns are pivotal in the empirical treatment of anaerobic infections. We determined the antimicrobial resistance patterns of clinically important anaerobic bacteria, including recently named or renamed anaerobes.
Methods: A total of 521 non-duplicated clinical isolates of anaerobic bacteria were collected from a tertiary-care hospital in Korea between 2014 and 2016. Anaerobes were isolated from blood, body fluids, and abscess specimens. Each isolate was identified by conventional methods and by Bruker biotyper mass spectrometry (Bruker Daltonics, Leipzig, Germany) or VITEK matrix-assisted laser desorption ionization time-of-flight mass spectrometry (bioMérieux, Marcy-l’Étoile, France). Antimicrobial susceptibility was tested using the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, tetracycline, and metronidazole.
Results: Most Bacteroides fragilis isolates were susceptible to piperacillin-tazobactam, imipenem, and meropenem. The non-fragilis Bacteroides group (including B. intestinalis, B. nordii, B. pyogenes, B. stercoris, B. salyersiae, and B. cellulosilyticus) was resistant to meropenem (14%) and cefotetan (71%), and Parabacteroides distasonis was resistant to imipenem (11%) and cefotetan (95%). Overall, the Prevotella and Fusobacterium isolates were more susceptible to antimicrobial agents than the B. fragilis group isolates. Anaerobic gram-positive cocci exhibited various resistance rates to tetracycline (6–86%). Clostridioides difficile was highly resistant to penicillin, cefoxitin, imipenem, clindamycin, and moxifloxacin.
Conclusions: Piperacillin-tazobactam, cefoxitin, and carbapenems are highly active β-lactam agents against most anaerobes, including recently named or renamed species.
Keywords: Antimicrobial resistance pattern, Anaerobes, Bacteroides, Korea

This Article



Indexed/Covered by