临床分离耐喹诺酮阴沟肠杆菌gyrA基因突变的研究  

Study on the mutation of gyrA gene in quinolone-resistant clinical isolates of Enterobacter cloacae

作　　者：于树云[1] 单志英[1] 祁伟[2] 葛庚芝[1] 毕玲[1] 司进[1] 

机构地区：[1]天津医科大学第二医院呼吸内科,天津300211 [2]天津医科大学第二医院感染疾病研究所

出　　处：《天津医科大学学报》2004年第2期240-242,共3页Journal of Tianjin Medical University

基　　金：天津医科大学科研基金资助 (编号 :2003ky46)

摘　　要：目的 :检测临床分离耐喹诺酮阴沟肠杆菌DNA促旋酶gyrA基因突变情况。方法:收集临床分离耐喹诺酮阴沟肠杆菌30株及敏感株10株 ,测定其对萘啶酸、环丙沙星、氧氟沙星的最低抑菌浓度 (MIC) ;用聚合酶链反应(PCR)扩增gyrA基因部分片断 ,对PCR产物进行限制性片断长度多态性 (PCR -RFLP)及单链构象多态性(PCR -SSCP)分析 ,检测gyrA突变情况。结果:30株耐喹诺酮菌株都检测到gyrA基因突变 ,PCR -RFLP均显示两条不同于敏感株的电泳带 ,其PCR -SSCP则检测到4种不同于敏感菌的迁徙率条带 ;而10株敏感菌均未检测到gyrA基因突变。结论:阴沟肠杆菌对喹诺酮类药物耐药性与gyrA基因突变有关 ,gyrA基因第83位氨基酸密码子突变可能为其耐药的主要原因。Objective: To study the mutation of gyrA gene in quinolone-resistant clinical isolates of Enterobacter cloacae.Methods:Using age the micro broth diluent to determine the MICs of three quinolones of 30 quinolone-resistant and 10 quinolone-susceptible isolates,the gyrA gene in these isolates was amplified with polymerase chain reaction(PCR),then by restrictive fragments length polymorphism(RFLP) and single strand conformation polymorphism(SSCP) to detect the mutation of gyrA gene.Results:All 30 quinolone-resistant isolates were detected the mutation of gyrA gene,the results of PCR-RFLP of them revealed two stripes while the RFLP-SSCP revealed four kinds of stripe different from 10 quinolone-susceptible isolates.No mutation in gyrA gene of 10 quinolone-susceptible isolates and ATCC13047 was detected by PCR-RFLP and PCR-SSCP.Conclusions:Mutation of gyrA gene in clinical isolates of Enterobacter cloacae implicated in resistance to quinolones,the mutation of DNA gyrase at the 83rd amino acid may be play a principle role in the resistant to quinolones of Enterobacter cloacae isolates.

关 键 词：阴沟肠杆菌 喹诺酮 促旋酶 RFLP SSCP 

分 类 号：R372[医药卫生—病原生物学]