한국의 한 대학병원에서 수집된 Acinetobacter baumannii 임상분리주의 meropenem 내성에 대한 AdeABC 유출펌프의 역할

The role of AdeABC efflux pump to meropenem resistance in Acinetobacter baumannii clinical isolates collected from a university hospital in Korea

The aim of this study is to investigate the role of the AdeABC efflux pump to meropenem resistance in 116 clinical isolates of Acinetobacter baumannii collected from a university hospital in Korea. We performed real-time RT-PCR to test the relative expression of adeB efflux pumps gene in them. The ratio of meropenem MIC change due to carbonyl cyanide m-chlorophenylhydrazone (CCCP), efflux pump inhibitor, was calculated. It was judged that the efflux pump contributed to meropenem resistance when the changed ratio of meropenem MIC by CCCP was 4 or more. The mean and standard error of the adeB relative expression level in the susceptible and resistant groups to meropenem were 3.2±0.8 and 11.9±2.9, respectively and there was a significant difference between the two groups (p＜0.0001). The ratio of meropenem MIC changes due to CCCP to 4 or higher in the susceptible and resistant groups to meropenem were 17.4% and 20.4%, respectively, and there was no significant difference between them. No correlation was observed between the adeB expression and the ratio of meropenem MIC change due to CCCP. It is considered that the adeB efflux pump did not significantly affect meropenem resistance in most strains of A. baumannii tested in this study.