Spread of OXA-23-producing Acinetobacter baumannii ST2 and ST246 in a hospital in Japan

A total of 1085 strains of Acinetobacter sp. obtained from 280 medical institutions in the Chugoku and Shikoku areas of Japan were investigated between 2011 and 2013. Among these strains, 20 (1.84 %) showing meropenem or imipenem resistance with a MIC of >4 μg ml- 1 were detected. Of these 20 strains, the bla(OXA-23) gene was detected in 17 strains isolated from the same institution. The PFGE patterns of the 17 strains were separated into two clusters, and multi-locus sequence typing showed the sequence types (STs) to be ST2 and ST246. This investigation demonstrated that A. baumannii ST2 of international clone II, which has rarely been isolated in Japan, has not yet spread nationwide.