Identification of an OXA-58 carbapenemase in an unusual Portuguese Acinetobacter baumannii clinical isolate

Abstract number: P1508

Caneiras C., Ferreira T., Duarte A., da Silva G.

Objectives: Several carbapenem oxacillinases have been reported recently in A. baumannii. Our group characterised a multidrug resistant (MDR) clone producing an OXA-40 carbapenemase endemic in Portugal and Spain. Recently, imipenem-resistant isolates with slight different antibiogram has been found in a Central Hospital Santo Antonio dos Capuchos (HSAC) at Lisboa. The aim of this study was to screen for carbapenemases in A. baumannii imipenem-resistant isolates.

Methods: The isolates were grouped on basis of susceptibility profiles determined by VITEK 2 System® and RAPD profiles. Amplification was performed using specific primers for OXA type enzymes and class 1 integrons. Plasmid extraction was prepared by Kado & Liu method.

Results: Fifteen representative isolates were clustered in 4 groups: A1 (n = 3) susceptible to tobramycin and colistin; A2 (n = 3) susceptible to aminoglycosides (gentamicine, amikacin, tobramycin and netilmicin), colistin, tetracycline, intermediate/resistant to ceftazidime and levofloxacin; A3 (n = 3) susceptible to aminoglicosydes and colistin but intermediate to tetracycline and resistant to ceftazidime; and group A4 (n = 3) with variable susceptibility. OXA-40 enzyme was found in 10 isolates, not correlating with any particular group. The Ac 156976 isolate, included in group A4, showed an OXA-58 enzyme and was resistant to aminoglycosides, ceftazidime, and imipenem; susceptible to ciprofloxacin, intermediate to meropenem. The plasmidic blaOXA-58 gene was part of a class 1 integron gene cassette.

Conclusion: The study report the identification of an OXA-58 enzyme in Portugal for the first time, and highlight the possibility of an emergence of a new multidrug resistant clone and its dissemination.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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