Genetics and expression of the carbapenem-hydrolyzing oxacillinase genes blaOXA-51 and blaOXA-58 in Acinetobacter baumannii isolates from blood cultures in a university hospital in Athens, Greece

Abstract number: P1511

Galani I., Galani L., Sakka V., Souli M., Chryssouli Z., Giamarellou H.

Objectives: Molecular studies showed that carbapenem-resistant Acinetobacter baumannii strains isolated from blood cultures of hospitalised patients in the University General Hospital ``Attikon'', belonging to several clones, contain both blaOXA-58 and the naturally occurring blaOXA-51-like genes. The objective of our study was to examine the genetic structures surrounding the blaOXA-51 and blaOXA-58 oxacillinase genes.

Methods: A total of 27 imipenem-resistant (harbouring blaOXA-58 and blaOXA-51-like genes) isolates collected from blood cultures of hospitalised patients in the University General Hospital ``Attikon'', were studied. Analysis of the sequences bracketing the blaOXA-51 and blaOXA-58 genes were evaluated by PCR mapping using combinations of the ISAba primers and the blaOXA-51-like and blaOXA-58-like reverse primers (Poirel and Nordmann, 2006). Bacterial clones were identified by PFGE with ApaI.

Results: ISAba1 element was identified upstream of the blaOXA-51 gene in all clones of A. baumannii tested. Some variability of the promoter sequences identified upstream of the blaOXA-58 gene among the analysed isolates was indicated by our results. In all isolates an ISAba3 element was identified upstream of the blaOXA-58 gene but in some cases it was truncated by the insertion of ISAba2. Additionally the ISAba3 was present (not always at the same distance) upstream of the start codon of blaOXA-58. Another interesting feature was the presence of ISAba3 downstream of blaOXA-58.

Conclusions: This work identified variable genetic structures at the origin of acquisition and expression of a carbapenem-hydrolyzing b-lactamase OXA-58 harboured by non-clonally related A. baumannii isolates.

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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