title: Differences in phenotypic and genotypic characteristics among imipenem-non-susceptible Acinetobacter isolates belonging to different genomic species in Taiwan.
abstract: In this study, we investigated the distribution of genes encoding various carbapenemases as well as their association with carbapenem resistance in clinical isolates of Acinetobacter genomic species from Taiwan. A total of 129 imipenem-non-susceptible and 79 imipenem-susceptible isolates were examined, of which 185 (88.9%) were Acinetobacter baumannii. Among the 185 A. baumannii isolates, imipenem non-susceptibility was more common in isolates with ISAba1-bla(OXA-51-like) (72/75; 96%), bla(OXA-58-like) (33/33; 100%) or bla(OXA-24-like) (7/7; 100%) than in isolates with only bla(OXA-51-like) (4/72; 5.6%). A metallo-beta-lactamase (MBL) gene was present in two isolates of imipenem-resistant A. baumannii, and bla(OXA-58-like) was also present in these isolates. A total of 18% and 1% of imipenem-non-susceptible isolates of A. baumannii were resistant to tigecycline and colistin, respectively. Among the 23 isolates of non-baumannii Acinetobacter spp., bla(OXA-58-like) and MBL genes were widely disseminated in the imipenem-resistant isolates, and isolates with bla(OXA-58-like) and MBL genes had higher imipenem minimum inhibitory concentrations than those with bla(OXA-58-like) alone. Although the rate of non-susceptibility to colistin was 26.7% among the imipenem-non-susceptible isolates of non-baumanniiAcinetobacter, 93.3% and 100% were susceptible to ciprofloxacin and tigecycline, respectively. In conclusion, different isolates of imipenem-non-susceptible A. baumannii and non-baumanniiAcinetobacter contained different carbapenemases and had different antimicrobial susceptibilities.
authors.affiliation: Department of Medicine, Chutung Veterans Hospital, Chutung, Taiwan.
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Lee
authors.forename: Li-Yueh
authors.initials: LY
authors.lastname: Huang
authors.forename: Dung-Hung
authors.initials: DH
authors.lastname: Chiang
authors.forename: Chien-Pei
authors.initials: CP
authors.lastname: Chen
authors.forename: Te-Li
authors.initials: TL
authors.lastname: Chen
authors.forename: Fu-Der
authors.initials: FD
authors.lastname: Wang
authors.forename: Chang-Phone
authors.initials: CP
authors.lastname: Fung
authors.forename: Leung-Kei
authors.initials: LK
authors.lastname: Siu
authors.forename: Wen-Long
authors.initials: WL
authors.lastname: Cho
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D014644:Genetic Variation; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013624:Taiwan; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D015378:Imipenem; D001618:beta-Lactamases