Increasing prevalence of bla_OXA-23-carrying Acinetobacter baumannii and the emergence of bla_OXA-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.