主动外排系统作为鲍曼不动杆菌耐环丙沙星重要机制的研究  

Study of Active Efflux System as an Important Mechanism Resistant to Ciprofloxacin in Acinetobacter baumannii

作　　者：范志茹[1] 夏忠弟[1] 周秩权[1] 周黎[2] 

机构地区：[1]中南大学湘雅医学院微生物学系,长沙410078 [2]黔东南民族职业技术学院,凯里556000

出　　处：《贵州科学》2009年第3期67-70,75,共5页Guizhou Science

摘　　要：目的探讨耐环丙沙星鲍曼不动杆菌的主动外排机制。方法试管稀释法检测56株临床鲍曼不动杆菌对环丙沙星的敏感性;用直接荧光法检测耐药株在有无外排泵抑制剂时鲍曼不动杆菌胞内药物聚集浓度;结合药敏和直接荧光法两项结果筛选出6株外排抑制剂存在时胞内药物聚集浓度明显升高的环丙沙星耐药株,对该耐药组及对照敏感组做胞内环丙沙星聚集浓度的线性测定;RT-PCR法检测两组菌株主动外排泵基因adeABC的表达水平;对adeABC自身启动子区域相关基因片段进行PCR扩增并测序。结果(1)56株鲍曼不动杆菌中,48株对环丙沙星耐药(M IC>4mg/l);0株对环丙沙星中介(1mg/l≤M IC≤4mg/l);8株对环丙沙星敏感(M IC<1mg/l)。(2)耐药组药物积累量不及敏感组,加入外排泵抑制剂叠氮化钠后积累量上升并接近敏感组。(3)耐药组主动外排基因adeB的表达水平(2.372±0.032)明显高于敏感组(1.654±0.040)(P<0.01)。(4)自身启动子区域相关基因片段没有发现突变。结论鲍曼不动杆菌对环丙沙星的耐药现象非常严峻;外排泵基因adeABC的过度表达是鲍曼不动杆菌对环丙沙星耐药的重要原因;adeABC基因自身启动子区域无导致adeABC过度表达的基因突变。Objective： To investigate the function and gene expression of active efflux system in ciprofloxacin - resistant Aeinetobacter baumannii. Methods： The susceptibility of 56 strains of clinical Aeinetobacter baumannii to ciprofloxacin was tested by tube dilution method. The efflux of clinical eiprofloxacin - resistant Aeinetobacter baumannii was tested, then strains with significantly increased efflux of ciprofloxaein were screened out. Reverse transcriptase polymerase chain reaction （ RT - PCR ） was used to measure the mRNA expression level of active effiux gene adeABC. Promoter region of adeABC was amplificated and sequenced . Results： 48 stains were resistant to ciprofloxacin. Accumulation of drug resistant group upgraded and reached that of sensitive group after NaN3 added. The express level of adeB of drug resistant group was higher than sensitive group obviously. Self-promoter region had no sense mutation. Conclusion Ciprofloxacin resistance in Acinetobacter baumannii is very serious. The excessire expression of active efflux pump gene is subscribed to the drugs active efflux of acinetobacter baumannii. Selfpromoter region has no sense mutation.

关 键 词：鲍曼不动杆菌 主动外排泵 外排泵抑制剂 adeABC 

分 类 号：O641.3[理学—物理化学]