The efflux pumps in clinical Acinetobacter baumannii isolates
Objective To study the expression of active efflux pump AdeABC,AdeIJK,AdeFGH,AbeM,AbeS,CraA,MdtL in clinical Acinetobacter baumannii isolates and whether the efflux pumps confers resistance to antibiotics.Methods Thirty-two multi-drug resistant Acinetobacter baumannii islates and 10 sensitive isolates were collected.Genes of the exporter protein were amplified by PCR.The expression of adeB,adeJ,adeG,abeM,abeS,craA,mdtL were examined by real-time fluorescence quantitative RT-PCR.The controlling genes adeRS and adeL were amplified by PCR and sequenced.Results The positivity rates of adeB,adeJ,adeG,abeM,abeS,craA,mdtL were 100％,100％,100％,96.88％,100％,100％ and 93.75％ respectively in 32 multi-drug resistant Acinetobacter baumannii isolates,and all 100％ in 10 sensitive isolates.The difference of expression of adeB,abeM and mdtL were significant( P＜0.001,P =0.001,P=0.013) between 21 multi-drug resistant isolates of C clone and 10 sensitive isolates.The mutations of adeRS existed in 2 multi-drug resistant isolates,no point mutation of adeL.Conclusion The expression of AdeABC,AbeM and MdtL may involved in the resistant mechanisms of the clinical Acinetobacter baumannii islates. 
 
Key words: 
Acinetobacter baumannii; Multi-drug resistance; Efflux pump