Outbreak of imipenem-resistant Acinetobacter calcoaceticus–Acinetobacter baumannii complex harboring different carbapenemase gene-associated genetic structures in an intensive care unit (original) (raw)

2012, Journal of Microbiology, Immunology and Infection

Background and Purpose: To investigate the clinical and molecular epidemiology of the imipenem-resistant Acinetobacter calcoaceticuseAcinetobacter baumannii (IRAcb) complex during an outbreak in an intensive care unit (ICU). Methods: Forty-six clinical and 11 environmental isolates of the IRAcb complex were collected from the ICU of Taipei Veterans General Hospital, Taiwan between December 2003 and March 2004. These isolates were genotyped using pulsed-field gel electrophoresis (PFGE). Carbapenemase genes and their associated genetic structures were analyzed using PCR. Clinical data obtained from the patients were also reviewed and analyzed. Results: The isolates were identified at the genomic species level as A. baumannii (42 clinical and five environmental isolates) and Acinetobacter genomic species 13TU (four clinical and six environmental isolates). Both species were comprised of two pulsotypes, but those of A. baumannii were closely related (83% similar). IS1008-DISAba3-bla OXA-58-like and ISAba1-bla OXA-51-like were identified in 22 and 21 clinical isolates of A. baumannii, respectively (one isolate contained both). The ISAba3-bracketed bla OXA-58-like gene was detected in all isolates of Acinetobacter genomic species 13TU. Patient transfers between different sections of the ICU were important factors that contributed to the spread of the two pulsotypes of A. baumannii. However, among the A. baumannii isolates identified, only those carrying IS1008-DISAba3-bla OXA-58-like could be