临床分离人型支原体基因突变与喹诺酮耐药相关性研究

DNA Gyrase and topoisomerase Ⅳ mutations in clinical isolates of mycoplasma hominis resistance to quinolones

目的探讨自我院临床所分离的人型支原体(Mycoplasma hominis,Mh)对喹诺酮类药物耐药的分子生物学机制。方法从泌尿生殖道标本中分离对喹诺酮类药物不同耐药谱表型的Mh21株,采用PCR方法分别检测其DNA旋转酶和DNA拓扑异构酶Ⅳ保守区基因序列,与对喹诺酮类药物敏感的模式菌株ATCC23114及基因库中的野生型菌株PG21基因序列进行比对,分析Mh DNA旋转酶以及拓扑异构酶Ⅳ氨基酸变异与其耐药性的关系。结果对司帕沙星耐药的11株Mh均检出GyrA83位Ser→Leu氨基酸变异;对氧氟沙星和左氧氟沙星耐药或中介的19株Mh中有16株检出ParC134位Lys→Arg氨基酸变异。结论 Mh GyrA基因83位Ser→Leu变异,可能与其对司帕沙星耐药相关;ParC134位Lys→Arg变异可能与其对氧氟沙星和左氧氟沙星耐药有关。

Objective To investigate the drug resistance mechanisms of Mycoplasma hominis against quinolones.Methods 21 strains of Mh with three kinds of different quinolone resistance phenotypes were isolated from genitouri- nary tract excretas. Detecting the DNA helicase gene and topoisomerase Ⅳ sequence of those strains by PCR,comparing sequence of them with sequence of standard strain ATCC 23114 sensitive to quinolones and wild-type strain PG21 from the genbank. Analyzing the relationship between Mh DNA helicase and top0isomerase IV conserved domain mutation sites and strain drug resistant phenotypes. Results Twenty-one clinical isolates of Mycoplasma hominis were examined for resistance to quinolones, mutations at positions 83 in GyrA （Escherichia colinumbering） and positions 80 and 134 in ParC were found. Unusual alterations were described at positions GyrA 56,15arc 80 and Pare 426 and 447. Conclusion Mh GyrA gene corresponding to 83 Ser→Leu mutation is related to it s-drug resistance to Sparfloxacin, Mh ParC gene corresponding to 134 Lys→Arg mutation is related to it＇s drug resistance to ofloxacin and levofloxaein.