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Carbapenemase producing clinical isolates among non-fermenting bacteria from a tertiary hospital

Abstract number: 1733_507

Perimeni D., Trifynopoulou K., Giakouppi P., Vourli S., Alevizos A., Zarkotou O., Tsimettas I., Gianneli D., Kalapothaki V., Vatopoulos A.

Objectives: The aim of our study was to investigate the distribution of metallo-b-lactamase producing strains and their molecular characteristics in non fermenting bacteria isolated from clinical specimens from a tertiary General Hospital in Piraeus, Greece in an 18-month period.

Methods: 110 strains of Pseudomonas aeruginosa and 57 strains of Acinetobacter calcoaceticus baumannii have been obtained mainly from blood and wound cultures, between 2002 and 2004. Antibiotic resistance was identified by disc diffusion tests and by determination of the MICs. All carbapenem-resistant P. aeruginosa and A. baumannii isolates were tested for the possible presence of MBL by placing a home-made disc containing 750 g EDTA 20 mm away from one containing imipenem 10 mg, confirmed with E-test MBL combination strips when the expansion was marginal. The presence of the carbapenemase-encoding genes blaVIM-1 and blaVIM-2 was tested by PCR. Genomic DNA of the blaVIM producing P. aeruginosa isolates, was digested with SpeI enzyme and processed for typing by Pulsed-field gel electrophoresis.

Results: 49 (44.5%) of P. aeruginosa and 24 (42%) of A. calco. baumannii isolates were carbapenem resistant. Of those, after further testing, 19 P. aeruginosa isolates were found to contain a blaVIM gene, while no A. calco. baumannii strain carried a metallo-b-lactamase. 18 P. aeruginosa isolates carried a blaVIM-2 gene and PFGE analysis showed a single pattern with two subtypes, while one strain carried a blaVIM-1 gene. All blaVIM genes were located in class 1 integrons.

Conclusion: Almost 39% of the carbapenem resistant P. aeruginosa isolates were blaVIM positive, while carbapenemase production did not seem to contribute in the resistance of infections caused by carbapenem resistant A. baumannii isolates in our hospital. The clonality of blaVIM-2 P. aeruginosa isolates implies that strict measures should be implemented in order to control the further spread of resistance.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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