Detection of intrinsic blaOXA-51-like by multiplex PCR on its own is not reliable for the identification of Acinetobacter baumannii.

Abstract Three clinical A. baumannii isolates Ab-508, Ab-511, and Ab-653 were recovered from South Africa, South Korea, and Turkey, respectively. Multiplex PCR to detect OXA-type carbapenemases showed atypical bla OXA-51-like amplification products. The aim of this study was to investigate the background of changes in bla OXA-51-like PCR products. Isolates were confirmed as A. baumannii using gyrB multiplex and rpoB sequencing and were epidemiologically unrelated by rep-PCR-based DiversiLab. Sequencing of bla OXA-51-like revealed an insertion of IS Aba15 in bla OXA-66 (isolate Ab-511) and an insertion of the novel IS Aba19 in bla OXA-78 (isolates Ab-508 and Ab-653). Detection of the intrinsic bla OXA-51-like by OXA-multiplex PCR should not be considered a fully reliable method for identification of A. baumannii when used without an additional independent method. Other species identification methods such as gyrB multiplex PCR and rpoB sequencing should be used to reliably identify A. baumannii .