Dissemination of VIM-1- and VIM-4-producing Acinetobacter baumannii clones in an intensive care unit
Abstract number: P903
Poulou A., Spanakis N., Markou F., Ikonomidis A., Pournaras S., Diomidous M., Vrizas D., Tsakris A., Rozi P.
Objectives:Acinetobacter baumannii complex are opportunistic pathogen with increasing relevance in hospital infections, especially among patients hospitalised in intensive care units (ICUs). The organism often exhibits multidrug resistance and recently outbreaks of carbapenem-resistant isolates have been reported worldwide. Acinetobacters develop resistance to carbapenems through various mechanisms including production of metallo-b-lactamases (MBLs). In Europe, carbapenem resistance has been only sporadically attributed to the production of MBLs. We describe the dissemination of two different VIM-type MBLs among clonal carbapenem-resistant A. baumannii isolates in a Greek ICU.
Methods: During a two year period (April 2005-March 2007) 24 MBL-producing carbapenem-resistant A. baumannii isolates were collected consecutively from clinical specimens of separate patients hospitalised in a medical-surgical Greek ICU. The isolates were tested by MICs, phenotypic MBL testing and PFGE. PCR and sequencing assays were used for identification of carbapenemase genes and mapping of integrons. The location of the MBL genes was investigated by PCR, curing and hybridisation experiments.
Results: The MBL-producers had multidrug-resistant phenotypes and clustered in two distinct clones. All 19 isolates of the predominant clone contained blaVIM-1 along with blaOXA-58 and the intrinsic blaOXA-66 carbapenemase gene. The remaining 5 isolates belonged to a distinct clone and contained blaVIM-4 along with the intrinsic blaOXA-69 carbapenemase gene. In all cases blaVIM alleles were integrated in class 1 integron variable structures. A. baumannii isolates belonging to the two VIM-producing clones were also detected in the environment of the ICU. PCR, curing and hybridisation experiments indicated that the blaVIM alleles were chromosomally-located.
Conclusions: This study illustrates the spread of blaVIM-1 and blaVIM-4 MBL genes among different clones of multidrug-resistant A. buamannii in a well defined clinical setting.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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