title: Antimicrobial susceptibility of clinical isolates of Bacteroides fragilis group organisms recovered from 2009 to 2012 in a Korean hospital.
abstract: BACKGROUND
  Periodic monitoring of antimicrobial resistance trends of clinically important anaerobic bacteria such as Bacteroides fragilis group organisms is required. We determined the antimicrobial susceptibilities of clinical isolates of B. fragilis group organisms recovered from 2009 to 2012 in a tertiary-care hospital in Korea.
  
  
  METHODS
  A total of 180 nonduplicate clinical isolates of B. fragilis group organisms were collected in a tertiary care hospital. The species were identified by conventional methods: the ATB 32A rapid identification system (bioMérieux, France) and the Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMérieux). Antimicrobial susceptibility was determined by the CLSI agar dilution method.
  
  
  RESULTS
  Imipenem and meropenem resistance rates were 0-6% for B. fragilis group isolates. The rate of resistance to piperacillin-tazobactam was 2% for B. fragilis and 0% for other Bacteroides species, but 17% for B. thetaiotaomicron isolates. High resistance rates to piperacillin (72% and 69%), cefotetan (89% and 58%), and clindamycin (83% and 69%) were observed for B. thetaiotaomicron and other Bacteroides spp. The moxifloxacin resistance rate was 27% for other Bacteroides spp. The MIC50 and MIC90 of tigecycline were 2-4 µg/mL and 8-16 µg/mL, respectively. No isolates were resistant to chloramphenicol or metronidazole.
  
  
  CONCLUSIONS
  Imipenem, meropenem, chloramphenicol, and metronidazole remain active against B. fragilis group isolates. Moxifloxacin and tigecycline resistance rates are 2-27% and 8-15% for B. fragilis group isolates, respectively.
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jisook
authors.initials: J
authors.lastname: Yim
authors.affiliation: Department of Laboratory Medicine, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Yangsoon
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Myungsook
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Seo
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Wan Hee
authors.initials: WH
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dongeun
authors.initials: D
authors.lastname: Yong
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yunsop
authors.initials: Y
authors.lastname: Chong
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001442:Bacteroides Infections / Q000382:microbiology* / Q000473:pathology; D001441:Bacteroides fragilis / Q000187:drug effects* / Q000302:isolation & purification; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D056910:Republic of Korea; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000078142:Tazobactam; D062606:Tertiary Care Centers; D013845:Thienamycins / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D013845:Thienamycins; D015378:Imipenem; D010397:Penicillanic Acid; D000077731:Meropenem; D000078142:Tazobactam; D010878:Piperacillin
keywords: Antimicrobial resistance; Bacteroides fragilis group; Moxifloxacin; Tigecycline