Abstract: Objective To investigate efflux pump drug-resistance and gene expression in multidrug resistant and pandrug resistant Acinetobacter baumannii.Methods The multidrug resistant Acinetobacter baumannii efflux pump phenotypes were detected by joining carbonyl cyanidem-chloropheny hydrazone (CCCP)pump inhibitors,the minimum inhibitory concentration (MIC)variation was observed in 9 6 strains of Acinetobacter baumannii resistant to tetracycline, norfloxacin,gentamicin,cefotaxime,34 strains of efflux phenotype positive Acinetobacter baumannii were screened out.The efflux pump protein gene adeB in 34 Acinetobacter baumannii were detected and sequenced with the polymerase chain reaction amplification.Results The initial selection involoed 34 strains (35.42%)whose MIC reduced by 4 times and above.In 34 stains of efflux pump phenotype positive Acinetobacter baumannii,33 strains were detected adeB gene,the positive rate was 97.06%.When the 33 strains Aacinetobacter baumannii adeB efflux pump gene were sequenced,the sequence homology was 100.00% compared in Genebank.Conclusion Pump inhibitor CCCP plays an important role in the reversal of Acinetobacter baumannii resistant to tetracycline,norfloxacin,gentamicin and cefotaxime,active efflux pump genes play an important role in multidrug resistant Acinetobacter baumannii.

Key words: acinetobacter baumannii, drug resistance, multiple, gene expression