烧伤患者鲍曼不动杆菌外排泵adeAB表达变化及其与细菌耐药的关系

Relationship of drug resistance in acinetobacter baumannii isolated from the burn patients with the expression alteration of effiux pump adeAB

目的检测从烧伤患者分离的鲍曼不动杆菌外排泵基因簇adeAB的表达，分析其上游调节基因adeR和adeS的表达变化，探讨这些基因改变对细菌耐药的影响。方法选取2012年6月-2013年3月烧伤患者来源的鲍曼不动杆菌耐药菌株9株、敏感菌株9株，经16SrDNA测序进行菌种鉴定后，以其标准菌株ATCCl960为参照，采用实时定量PT-PCR技术分别检测外排泵基因adeA、adeB及上游调节基因adeR、adeS的mRNA相对表达量。结果（1）耐药菌株组adeA、adeB的表达量分别为3．71±0．95和76．16±8．75，均高于敏感菌株组的0．92±0．94和0．72±0．78（F值分别为38．7l，663．65，P均〈0．05）；（2）耐药菌株组adeS、adeR的表达量分别为18．02±6．71和3．02±2．69，均高于敏感菌株组的1．64±1．51和0．76±0．61（F值分别为51．04，5．57，P均〈0．05）。结论上游调节基因adeS、adeR表达变化导致外排泵基因簇adeAB表达增加，是烧伤患者鲍曼不动杆菌耐药的重要原因之一。而调节基因的这种变化可能与细菌通过adeS感应医院内环境条件，活化或钝化adeR，从而调控外排泵的表达有关。

Objective To observe the expressions of efflux pump gene cluster adeAB in acinetobacter baumannii isolated from the burn patients and the expression changes of its upstream regulatory genes adeR and adeS and determine the influence of those genes on drug resistance of acinetobacter baumannii. Methods Nine drug-resistant strains and nine sensitive strains of acinetobacter baumannii isolated from the burn patients treated between June 2012 and March 2013 were used. After strain identification using 16SrDNA sequencing, acinetobacter baumannii standard strain ATCC19606 was employed as the control, mRNA expressions of efflux pump genes adeA and adeB and their upstream regulatory genes adeR and adeS were detected by real-time quantitative PCR. Results （ 1 ） adeA and adeB genes presented higher expressions in drug-resistant strains （3.71 ± 0.95, 76.16 ± 8.75 ） than in sensitive strains （0.92 ± 0.94, 0.72 ± 0.78） （ F = 38.71, 663.65 respectively, both P 〈 0.05 ）＇. （2） adeS and adeR genes showed higher expressions in drug resistant strains （ 18.02 ± 6.71, 3.02 ± 2： 69） than in sensitive strains （1.64±1.51, 0.76 ±0.61） （F = 51. 04 , 5. 57 respectively , bothP〈O. 05） Conclusions The over-expression of efflux pump gene cluster adeAB induced by the expression alteration of its upstream regulatory genes adeR and adeS is closely associated with the drug resistance of acinetobacter banmannii in the burn patient. Besides, the regulatory genes may depend on adeS to sense the nosocomial environment condition, activate or inactivate adeR and hence regulate efflux pump expression. ＇