Relationship between expression and antimicrobial resistance of RND efflux pump of Acinetobacter baumannii / 中国感染控制杂志

ABSTRACT

Objective To detect the distribution of resistance-nodulation (RND)efflux pump system of Acineto-bacter baumannii (AB),and explore the relationship between its’expression and antimicrobial resistance.Methods Fifty-nine strains of multidrug-resistant AB isolated from clinical specimens in The First Affiliated Hospital of Nan-chang University were identified and performed antimicrobial susceptibility analysis,distribution of RND efflux sys-tem of AB was detected by polymerase chain reaction(PCR),expression of efflux pump genes in different drug-re-sistant phenotypes of AB was compared,relationship between the expression level and drug resistance was analyzed, amplified products of RND efflux system were sequenced.Results Resistance rates of AB to ampicillin/sulbactam, imipenem,gentamicin,ciprofloxacin,and levofloxacin were 93.2%,94.9%,88.1%,96.6%,and 52.5% respec-tively.PCR detection results of efflux pump and integron genes of 59 AB strains revealed that the carrying rates of adeR,adeS,adeB,adeJ,and adeG genes were 81.4%,91.5%,93.2%,100.0%,and 61.0% respectively.The expression of efflux pump genes in different strains was different,expression levels of ade B and adeJ genes among gentamicin,imipenem,ampicillin/sulbactam resistant AB group and non-resistant AB group were significantly dif- ferent (all P＜0.05).There was no mutation or insertion sequence in the base sequences of regulatory genes ade R and ade S of adeABC efflux pump.Conclusion RND efflux pump system is universally present in AB,the expres-sion upregulation of ade B and ade J genes in RND efflux pump system is related with antimicrobial resistance of bacteria to gentamycin,imipenem,and ampicillin-sulbactam.