Study On Correlation Between Pan-drug Resistance With Efflux Pump And Outer Membrane Protein In Acinetobacter Baumannii

Objective To determine the in vitro activities of13antimicrobials includingCefoperazone-sulbactam against clinical isolates of Acinetobacter baumannii and provideexperimental evidences for rational use of antimicrobial agents. To investigate the functionthat induce pan-drug resistance and gene expression of active efflux pump and outermembrane protein in Acinetobacter baumannii.Methods A total of100non-repeated strains of Acinetobacter baumannii wereisolated from clinical specimens in The First Affiliated Hospital of Suchoow Universityand all of them had been re-identified by manual test and VITEK ⅡCompact ofBio-Merieux.First part The susceptibilities of100strains clinical Acinetobacter baumannii wasdetermined by K-B and2-fold agar dilution method followed by NCCLS recommendations．Second part The genes adeB、adeJ and carO were amplified by PCR and the resultswere observed by agarose gel electrophoresis．Reverse transcriptase polymerase chainreaction （RT-PCR） was used to measure the mRNA expression levels of active effluxpump AdeABC、AdeIJK.Results First part The antibacterial activity of antibiotic frequently-used is poorerthan minocyline、polymixin B and sulperazone. There are75pan-drug resistant strains inall100strains, their resistant rate to Imipenem、minocyline、polymixin B and sulperazoneare88%、59.15%、0%and21.13%while the geometrical mean of MICs are25.16（resistance）、5.85（medium）、1.06（sensitive）和29.3（medium）.Second part The test result of adeB gene including PCR and RT-PCR reveal thedifferences between resistant strains and sensitive strains have statistical significant whilethe expression level of adeJ gene between the two groups have no significant difference; The carO gene was detected in98.57%pan-drug resistant strains.Conclusions The antibiotic resistance is very serious while minocyline、polymixin Band sulperazone with considerable antibacterial activities may be the choices formulti-drug resistant isolates infections of Acinetobacter baumannii．The positive rate ofadeB and adeJ gene is high in Acinetobacter baumannii. Besides, the expression level ofadeB gene obviously increased in pan-drug resistant strains and some sensitive strains.Theactive efflux pump AdeABC play a role in pan-drug resistance of Acinetobacter baumannii...