鲍氏不动杆菌耐喹诺酮类药物的机理研究  

Study on the mechanism of resistance in Acinetobacter baumannii to quinolones

作　　者：刘丁[1] 陈萍[1] 俞志海[1] 陈伟[1] 

机构地区：[1]第三军医大学大坪医院临床微生物与感染监控中心,重庆400042

出　　处：《中国抗生素杂志》2003年第3期168-171,共4页Chinese Journal of Antibiotics

基　　金：全军"十五"医药科研基金课题 (编号 0 1Q 0 96)

摘　　要：目的　研究鲍氏不动杆菌对喹诺酮类药物的耐药机制。方法　对临床上收集的耐环丙沙星鲍氏不动杆菌进行氟罗沙星摄取试验、外膜蛋白电泳、PCR扩增 gyrA和parC基因、酶切分析和测序。结果　耐药株药物聚积量不及敏感株的 1/2 ,经碳酰氰间氯苯腙 (CCCP)处理后 ,聚积量上升并接近敏感株 ;经SDS PAGE电泳 ,耐药株与敏感株比较 ,外膜蛋白在约 2 9ku条带处消失 ,而 2 4ku处条带却明显增强 ;PCR RFLP分析 ,gyrA基因能产生 1条DNA片段 ,而 parC基因则能产生 2条片段 ;测序结果显示 ,其GyrA蛋白中所编码 83位 (相应于大肠埃希氏菌 )氨基酸由丝氨酸变为亮氨酸 ,ParC蛋白未见氨基酸改变。结论　该株对环丙沙星耐药鲍氏不动杆菌存在DNA促旋酶变异 ,药物主动外运及外膜的改变。Objective To study the mechanism of resistance in Acinetobacter baumannii to quinolones. Methods A ciprofloxacin resistance clinical isolate was collected. Accumulation of fleroxacin by A.baumannii was determined. Outer memberane proteins was analyzed. The regions of gyrA and parC genes were amplified by polymerase chain reaction (PCR) and were digested by Hinf I . The products were sequenced. Results The accumulation of fleroxacin in resistante isolate decreased. After treatment with CCCP, the drug uptake increased to the normal level. The analysis of outer membrane protein showed that a protein of 29ku disappeared and 20～24ku protein enhanced in resistant isolate. Hinf I digestion of the gyrA gene product generated one fragment, the parC gene product generated two fragments. DNA sequencing analysis of gyrA revealed point mutation that resulted in amino acid change: Ser 83→Leu. There were not any changes in the parC gene. Conclusion These results indicated that the alteration of DNA gyrase, active drug efflux and outer membrance permeability decreasement were the factors contributing to the quinolone resistance of A.baumannii .

关 键 词：鲍氏不动杆菌 诺酮类药物 耐药性 主动外排 基因突变 外膜蛋白 

分 类 号：R978.19[医药卫生—药品] R378.99[医药卫生—药学]