鲍曼不动杆菌临床株的外排泵研究

The effiux pumps in clinical Acinetobacter baumannii isolates

目的探讨鲍曼不动杆菌临床株外排泵AdeABC、AdelJK、AdeFGH、AbeM、AbeS、CraA、MdtL的表达与耐药的关系。方法收集多重耐药鲍曼不动杆菌临床株32株和敏感株10株，PCR扩增泵基因；选取主要克隆型的21株多重耐药株和10株敏感株，实时荧光定量RT-PCR方法检测泵基因adeB、adeJ、adeG、abeM、abeS、craA、mdtL的mRNA相对表达水平，PCR扩增泵调控基因adeRS、adeL并测序分析。结果32株多重耐药鲍曼不动杆菌临床株中携带泵结构基因片段adeB100％、adeJ100％、adeG100％、abeM96．88％、abeS100％、craA100％、mdtL93．75％，10株敏感株均存在7种泵结构基因片段；主要克隆型的21株多重耐药株和10株敏感株adeB、abeM、mdtL的mRNA相对表达水平的差异有统计学意义（P〈O．001，P=0．001，P=0．013），选取多重耐药株AbR3和AbRll检测外排泵AdeABC调控基因adeRS序列出现氨基酸替代及缺失，而外排泵AdeFGH调控基因adeL序列无基因突变。结论鲍曼不动杆菌临床株外排泵AdeABC、AbeM、MdtL的表达可能与耐药性有关。

Objective To study the expression of active efflux pump AdeABC, AdeIJK, AdeF- GH, 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 expres- sion 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 posi- tivity 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 muhi-drug resistant isolates of C clone and 10 sensitive isolates. The mu- tations of adeRS existed in 2 multi-drug resistant isolates, no point mutation of adeL. Conclusion The ex- pression of AdeABC, AbeM and MdtL may involved in the resistant mechanisms of the clinical Acinetobacter baumannii islates.