title: Difference in imipenem, meropenem, sulbactam, and colistin nonsusceptibility trends among three phenotypically undifferentiated Acinetobacter baumannii complex in a medical center in Taiwan, 1997-2007.
abstract: BACKGROUND
  To determine whether the susceptibilities and the trends of nonsusceptibility of imipenem, meropenem, sulbactam, and colistin differed among Acinetobacter baumannii, Acinetobacter genomic species 3 (AGS 3), and Acinetobacter genomic species 13TU (AGS 13TU) over 11 years.
  
  
  METHODS
  A total of 1,039 nonduplicate blood isolates of A baumannii complex from bacteremic patients between 1997 and 2007 were collected at Taipei Veterans General Hospital and were identified to the species level using a multiplex polymerase chain reaction method and sequence analysis of 16S-23S intergenic spacer. The minimal inhibitory concentrations of antibiotics were determined by the agar dilution method.
  
  
  RESULTS
  The nonsusceptibility rates of carbepenems and sulbactam were highest in A baumannii, which also showed a trend toward increasing rate of carbapenems nonsusceptibility over the 11-year period of the study. AGS 13TU had the highest nonsusceptible rate to colistin, comparably increasing trend of carbapenem nonsusceptiblity as that of A baumannii, and is the only species with increasing sulbactam nonsusceptibility. AGS 3 had the lowest rate of nonsusceptibility to all four antimicrobial agents.
  
  
  CONCLUSIONS
  Although A baumannii had the highest nonsusceptibility rate to imipenem, meropenem, and sulbactam over the years, the higher rate of colistin nonsusceptibility and the emergence of nonsusceptibility of carbapenems and sulbactam in AGS 13TU suggested that this species might cause a great problem in the near future.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chen
authors.initials: C
authors.lastname: Liang-Yu
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Kuo
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Liu
authors.forename: Bin-Syun
authors.initials: BS
authors.lastname: Luo
authors.forename: Ling-Ju
authors.initials: LJ
authors.lastname: Huang
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Lee
authors.forename: Chien-Pei
authors.initials: CP
authors.lastname: Chen
authors.forename: Te-Li
authors.initials: TL
authors.lastname: Chen
authors.forename: Chang-Phone
authors.initials: CP
authors.lastname: Fung
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D016000:Cluster Analysis; D003091:Colistin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005838:Genotype; D006787:Hospitals, Veterans; D006801:Humans; D008826:Microbial Sensitivity Tests; D060885:Multiplex Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013407:Sulbactam / Q000494:pharmacology*; D013624:Taiwan; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D047090:beta-Lactams; D013407:Sulbactam; D003091:Colistin