Detection of VIM2 metallo-lactamase in Pseudomonas aeruginosa isolates from two central hospitals in Portugal

Abstract number: P1493

Reis T., Ribeiro G., Vital C., Alves A., Cardoso O.

Objective:Pseudomonas aeruginosa (PA) is one of the leading causes of nosocomial infections as it is an opportunistic human pathogen with an amazing capacity to resist antibiotics either intrinsically or following acquisition of resistance genes. The aim of this study was to identify metallo-b-lactamases (MBLs) in imipenem resistant isolates obtained from two central hospitals belonging to the centre region of Portugal.

Methods: Imipenem resistant bacterial isolates (n = 91) from Centro Hospitalar de Coimbra (CHC) were collected from June 2007 to June 2008 (one year) and 31 from Hospitais da Universidade de Coimbra (HUC) collected from January 2008 to June 2008 (half year). Double-disk synergy test was used for screening MBLs. For research of blaVIM, blaIMP, blaGIM, and blaSPM, PCR was done. PCR products obtained were sequenced and analysed. The minimal inhibitory concentration (MICs) of the VIM-2 isolates was determined by E-test method.

Results: The double disk synergy test was positive in 32 isolates from CHC and in 18 of HUC. The presence of blaVIM was positive in 12 from CHC and 15 from HUC, and DNA sequencing showed the presence of blaVIM-2 gene in all of the 27 isolates (54%). The other metallo-b-lactamases tested were not observed. Among the strains that harboured VIM-2, MICs were determined and the results revealed that aztreonam inhibited 81.5% followed by piperacillin 66.7%, ceftazidime 25.9%, and meropenem 22.2%.

Conclusions: Our findings are of concern since they demonstrate that VIM-2 can emerge and turn into a major cause of broad spectrum b lactam resistance among nosocomial pathogens. The monitoring of these non-fermenting Gram negative bacilli for production of metallo-b-lactamases should become a standard aspect of any local or global surveillance systems.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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