摘要
目的探讨主动外排系统AcrAB—TolC在志贺菌对氟喹诺酮类抗生素耐药性中的作用。方法K．B纸片扩散法及MIC测定2009-2011年天津地区临床分离的144株志贺菌的药敏情况；加入泵抑剂UCCCP（羰基氰氯苯腙）检测耐药菌株对氟喹诺类抗生素敏感性的变化；应用定量PCR研究外排泵基因acrAB-tolC表达以探讨外排泵在菌株对氟喹诺酮耐药中的作用。结果144株志贺菌中，共有5株志贺菌对环丙沙星等氟喹诺酮类抗生素耐药，均为福氏志贺菌。加入泵抑制剂后，5株志贺菌对5种氟喹诺酮类抗生素的MIC下降了4-16倍，而对照菌株对上述药物的MIC没有变化或仅下降至原值的1／2。实时定量PCR结果表明耐药菌株外排泵基因acrA、ac坷和细，c的mRNA水平显著高于敏感野生株（P〈0．05）。结论本地区志贺菌临床株对氟喹诺酮类抗生素环丙沙星及氧氟沙星耐药率最高，为3．47％。AcrAB-TolC外排泵基因的高表达是导致志贺菌对氟喹诺酮类抗生素耐药的主要原因之一。
Objective To investigate the effects of the AcrAB-TolC Pump on the mechanism of fluoroquinolone-resistance of clinical isolates of Shigella. Methods A total of 144 clinical isolates of Shigella identified in Tianjin from 2009 to 2011 were analysed for their antimicrobial susceptibility detected by K-B disk diffusion method and the minimal inhibitory concentratio（MIC）. Efflux pump inhibitor CCCP was added to find the change in MICs. Expression levels of acrAB-toIC mRNA were calculated by Real-time PCR to analyse effects of the AcrAB-TolC Pump on resistance to fluoroquinolone of clinical isolates of Shigella. Results Among 144 Shigella strains, 5 isolates of Shigella flexneri are resistant to fluoroquinolon such as ciprofloxacin, all of them are S. flexneri isolates. After the addition of CCCP, MICs of five resistant isolates to five kinds of fluoroquinolone are decreased 4-16 times, however, the MICs of control strains have little change. Results of real-time PCR show the expression level of acrA, acrB and tolC gene in the five resistant strains was significantly higher than that in the susceptible strains（P〈0.05）. Conclusion In our area, Shigella clinical isolates have the highest resistant rate of 3.47% to ciprofloxacin and ofloxacin. Overexpression of efflux pump gene is one of the main reasons of fluoroquinolone resistance in Shigella.
出处
《中国抗生素杂志》
CAS
CSCD
北大核心
2013年第9期696-699,共4页
Chinese Journal of Antibiotics
基金
天津医科大学校级课题(2010KY47)
关键词
志贺菌
氟喹诺酮
外排泵
Shigella
Fluoroquinolone
Effiux pump
