鲍曼不动杆菌对喹诺酮类耐药机制
Study on mechanism of resistance in acinetobacter baumannii to quinolones
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摘要:目的 探讨鲍曼不动杆菌对氟喹诺酮类药物的耐药机制。方法 采用K-B法检测35株鲍曼不动杆菌对氟喹诺酮类药物的药敏情况, 十二烷基磺酸钠-聚丙酰胺凝胶电泳(SDS-PAGE)法检测鲍曼不动杆菌的外膜蛋白(OMP), 直接荧光法检测鲍曼不动杆菌对环丙沙星的吸收和积累, PCR法扩增gyrA基因并对其进行测序。结果 35株鲍曼不动杆菌中有20株对氟喹诺酮类药物耐药, 耐药菌株与敏感菌株相比, 外膜蛋白在约29Ku条带处消失, 在26Ku条带处明显增强。耐药菌株药物积累量不及敏感菌株, 经叠氮钠处理后, 积累量上升并接近敏感菌株, 对PCR扩增产物gyrA测序未发现有突变。结论 鲍曼不动杆菌对氟喹诺酮类药物的耐药与外膜蛋白的低通透性和主动外运有关。Abstract:Objective To study the mechanism of resistance in acinetobacter baumannii to quinolones.Methods Bacterial susceptibility test to quinolones were done by the Kirby-Bauer method for 35 isolates.Outer membrane protein was analyzed by SDS-PA GE.A ccumulation of ciprofloxacin by A.baumannii was determined by direct fluor escence method.The gene of gyrA was amplified by polymerase chain reaction(PCR)and the products were sequenced.Results 20 isolates were resistant to quinolones in 35 isolates.The analysis of outer membrane proteins showed that a protein of 29ku disappeared and 26ku protein enhanced in resistant isolates.The accumulation of ciprofloxacin in resistant isolates decreased.After treatment with NaN3, the drug uptake increased to the normal level.DNA sequencing analysis revealed there was not any mutation in the gyrA gene.Conclusion Active drug efflux and outer membrane protein permeability decreasement were the factors contributing to the quinolone resistance of A baumannii.
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