中文摘要：

目的研究临床分离的肺炎克雷伯菌中外排泵基因表达及其对环丙沙星耐药性的影响,明确外排泵在肺炎克雷伯菌对环丙沙星耐药中的作用。方法收集医院2014年9月-2015年2月临床标本中分离的肺炎克雷伯菌36株,采用VITEK-2Compact全自动微生物鉴定仪进行鉴定;K-B纸片扩散法对抗菌药物进行敏感性测定;用PCR方法检测菌株中的外排泵基因;用微量稀释法检测抗菌药物的最低抑菌浓度（MIC）以及泵抑制剂羰基氰氯苯腙（CCCP）存在情况下,肺炎克雷伯菌对环丙沙星MIC值的变化。结果 36株肺炎克雷伯菌中,有16株对环丙沙星耐药,耐药率为44.44%;采用PCR技术对16株耐药菌的外排泵acrAB基因进行检测,其中只有9株耐药菌株的检测结果为阳性,acrAB基因的检出率为56.25%;加入CCCP后,acrAB基因阳性株中,有5株（55.56%）MIC值下降4-16倍,2株（22.22%）MIC值下降两倍,还有2株（22.22%）MIC值未下降。结论 acrAB外排系统是肺炎克雷伯菌耐环丙沙星的一个重要机制,泵抑制剂CCCP可有效抑制acrAB基因的外排作用。

英文摘要：

OBJECTIVE To confirm the role of acrABefflux pump in mediating the resistance of Klebsiella pneumoniae isolated from clinic to ciprofloxacin,and to clear the contribution of efflux pump in K.pneumoniae to resistance of ciprofloxacin.METHODS Thirty-six strains of K.pneumoniae were isolated from our hospital during Sep.2014-Feb.2015.Bacteria were identified by VITEK-2Compact identification system;susceptibility to antibacterial agent was determined by the K-B disk diffusion method;the efflux pump genes were detected by polymerase chain reaction.The minimal inhibitory concentration（MIC）in antibacterial agent and the change of ciprofloxacin MIC to K.pneumoniae when there was efflux pump inhibitor carbonyl cyanide chlorobenzene phenylhydrazone（CCCP）were detected by microdilution method.RESULTS Sixteen out of the thirty-six K.pneumoniae isolates were resistant to ciprofloxacin and the resistance rate was 44.44%.PCR was used as the way for detecting the acrABgene of sixteen resistant strains,only nine strains with positive result and the acrABgene positive rate was 56.25%.After using CCCP as an efflux pump inhibitor,5strains of acrAB positive strains（55.56%）showed 4-to-16 fold reduction in MICs and 2strains（22.22%）showed 2-fold reduction in MICs,the other 2strains（22.22%）showed no disparity in MICs.CONCLUSION The acrABefflux system is one of the important mechanisms in ciprofloxacin resistance among K.pneumoniaeisolates,and CCCP can inhibit the effect of acrAB efflux system effectively.