人型支原体对喹诺酮类药物耐药机制的初步研究

目的探讨人型支原体(mycoplasma hominis,MH)对喹诺酮类药物的耐药机制。方法泌尿生殖道分泌物中分离的对3种喹诺酮类药物耐药的10株MH,采用PCR方法检测其DNA螺旋酶基因序列,与对喹诺酮类药物敏感的标准菌株ATCC23114及基因库中的野生型菌株PG21基因序列对比,分析MHDNA螺旋酶II保守区突变位点与菌株耐喹诺酮类药物的关系。结果与野生株(PG21)比较,对司帕沙星耐药的7株Mh均检出GyrA氨基酸残基S153→L变异,对应于大肠杆菌则为S83→L,4号株还同时检出对应于大肠杆菌S56→I变异。对司帕沙星敏感的Mh菌株及标准菌株则未发现GyrA中氨基酸残基变异。结论 Mh菌株GyrA基因编码的对应于大肠杆菌S83→L氨基酸残基变异与Mh耐司帕沙星相关。

Study on Drug Resistance Mechanisms of Mycoplasma Hominis to Quinolone

Objective To study the drug resistance mechanisms of Mycoplasma hominis(MH) against quinolone. Methods Ten strains of MH with three kinds of different quinolone resistance phenotype were isolated from urinary tract secretions. The DNA helicase gene sequence of the GyrA and GyrB in the ten isolates of MH with different phenotype resistance to quinolones and standard strain ATCC 23114 were detected. The sequencing results of the GyrA and GyrB were compared with wild-type strain PG21. Results Compared with wild strain (PG21), the S153-to-L substitution of GyrA, corresponding to Escherichia coli was S83-to-L substitutions, were found in 7 strains of isolates Mh resistant to Sparfloxacin, whereas the Mh isolates (No. 4) had S56-to-I substitutions. There was no amino acid residue mutation be found in the GyrA of Mh sensitive to Sparfloxacin and standard Mh strain. Conclusion The S83-to-L (corresponding to Escherichia coli number) substitution of GyrA was associated with Mh strains resistance to sparfloxacin.