Increasing prevalence of blaOXA-23-carrying Acinetobacter baumannii and the emergence of blaOXA-182-carrying Acinetobacter nosocomialis in Korea.

Carbapenem-resistant Acinetobacter spp. have been increasingly reported worldwide with the production of OXA-type carbapenemases as the main mechanism of carbapenem resistance. The prevalent bla(OXA) genes are known to vary significantly depending on time and place of isolation. We investigated the prevalence of bla(OXA) genes by PCR in Acinetobacter spp. isolated in Korea. Among a total of 336 isolates collected from Hospital A from 2002 to 2011, the overall proportion of bla(OXA)-23-like, ISAba1-associated bla(OXA-51)-like, and bla(OXA-182) genes were 44.0%, 49.7%, and 5.1%, respectively. The bla(OXA-58)-like gene was detected in only 1 isolate. A drastic increase in Acinetobacter isolates with bla(OXA-23)-like genes and a decrease in isolates harboring ISAba1-associated bla(OXA-51)-like genes have been observed since the mid-2000s. The bla(OXA-23)-like genes were detected in all carbapenem-nonsusceptible isolates collected in 2011 from 9 hospitals. The OXA-182, which belongs to the fifth group of OXA-type carbapenemase, was detected in Acinetobacter baumannii isolates recovered as early as 2002. It is worrisome results that bla(OXA-182)-carrying Acinetobacter nosocomialis has emerged and caused outbreaks of infection.