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-blaOXA-51-like (72/75; 96%), blaOXA-58-like (33/33; 100%) or blaOXA-24-like (7/7; 100%) than in isolates with only blaOXA-51-like (4/72; 5.6%). A metallo-β-lactamase (MBL) gene was present in two isolates of imipenem-resistant A. baumannii, and blaOXA-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., blaOXA-58-like and MBL genes were widely disseminated in the imipenem-resistant isolates, and isolates with blaOXA-58-like and MBL genes had higher imipenem minimum inhibitory concentrations than those with blaOXA-58-like alone. Although the rate of non-susceptibility to colistin was 26.7% among the imipenem-non-susceptible isolates of non-baumannii Acinetobacter, 93.3% and 100% were susceptible to ciprofloxacin and tigecycline, respectively. In conclusion, different isolates of imipenem-non-susceptible A. baumannii and non-baumannii Acinetobacter contained different carbapenemases and had different antimicrobial susceptibilities.
Date:
2009-12
Relation:
International Journal of Antimicrobial Agents. 2009 Dec;34(6):580-584.
