大肠埃希菌对氟喹诺酮类的耐药性及其机制研究  

Drug resistance of Escherichia coiland mechanisms of its resistance to fluoroquinolones

作　　者：陈枫[1] 梁海军[1] 钟利[1] 林雁[2] 唐小平[1] 陈庄[1] 黄永茂[1] 

机构地区：[1]泸州医学院附属医院感染科,四川泸州646000 [2]泸州医学院附属医院检验科,四川泸州646000

出　　处：《中华医院感染学杂志》2012年第5期884-886,共3页Chinese Journal of Nosocomiology

基　　金：四川省重点学科重点建设项目资助(SZD0241)

摘　　要：目的探讨大肠埃希菌(ECO)对氟喹诺酮类药物的耐药率及耐药机制。方法 K-B法测定100株ECO对5种氟喹诺酮抗菌药物的耐药性,试管稀释法测定耐环丙沙星和左氧氟沙星的最低抑菌浓度(MIC);错配PCR技术检测耐环丙沙星ECO gyrA基因和parC基因的突变。结果 100株ECO中耐环丙沙星有65株;环丙沙星MIC50、MIC90分别是32、128μg/ml,左氧氟沙星MIC50、MIC90是16、64μg/ml;基因位点结果显示,耐环丙沙星的65株中,有60株发生gyrA、parC一个或多个基因位点的突变,有5株未发生突变。结论 gyrA、parC基因突变是该地区ECO,对氟喹诺酮类药物耐药的重要机制,且基因突变位点越多其耐药程度越高。OBJECTIVE To investigate the drug resistance of Escherichia coli and the mechanisms of its resistance to fluoroquinolones.METHODS The drug resistance of 100 strains of E.coli to 5 kinds of fluoroquinolones was evaluated by KB method.The minimal inhibitory concentrations（MICs）of E.coil to ciprofloxacin and levofloxacin were determined by tube dilution method,and mutations in gyrA gene and parC gene of ciprofloxacin-resistant E.coil were detected by mismatch PCR method.RESULTS Of 100 strains of E.coil,there were 65 strains resistant to ciprofloxacin The MIC was different for different drug.For ciprofloxacin：MIC50 was 32μg/ml,MIC90 was 128μg/ml,and for Levofloxacin：MIC50 was 16μg/ml,MIC90 was 64μg/ml.Furthermore,the Mismatch PCR detection demonstrated that gyrA or parC of 60 strains of E.coil mutated at one or more geneticlocuses in the 65 ciprofloxacin-resistant E.coil strains.CONCLUSION The mutation of the gyrA and parC gene is an important mechanism for the fluoroquinolones resistance in the region,and the more mutations in gene encoding loci of the gyrA and parC,the more serious drug resistance developed.

关 键 词：大肠埃希菌 氟喹诺酮类 抗药性 基因突变 

分 类 号：R378.21[医药卫生—病原生物学]