Worldwide dissemination of the blaOXA-23 carbapenemase gene of Acinetobacter baumannii.

To assess dissemination of OXA-23-producing strains of Acinetobacter baumannii, we obtained 20 carbapenem-resistant, OXA-23-producing isolates from different regions. Their clonal relationship was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. We identified 8 sequence types, including 4 novel types. All except 2 strains belonged to 2 main European clonal lineages. The blaOXA-23 gene was either located on the chromosome or on plasmids and associated with 4 genetic structures.