Increasing prevalence of blaₒₓₐ₋₂₃-carrying Acinetobacter baumannii and the emergence of blaₒₓₐ₋₁₈₂-carrying Acinetobacter nosocomialis in Korea

Abstract

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 blaₒₓₐ genes are known to vary significantly depending on time and place of isolation. We investigated the prevalence of blaₒₓₐ 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 blaₒₓₐ₋₂₃-like, ISAba1-associated blaₒₓₐ₋₅₁-like, and blaₒₓₐ₋₁₈₂ genes were 44.0%, 49.7%, and 5.1%, respectively. The blaₒₓₐ₋₅₈-like gene was detected in only 1 isolate. A drastic increase in Acinetobacter isolates with blaₒₓₐ₋₂₃-like genes and a decrease in isolates harboring ISAba1-associated blaₒₓₐ₋₅₁-like genes have been observed since the mid-2000s. The blaₒₓₐ₋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 blaₒₓₐ₋₁₈₂-carrying Acinerobacter nosocomialis has emerged and caused outbreaks of infection.