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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。
Objective To investigate the mechanism of quinolone resistance in human mycoplasma hominis (MH). Methods Ten MH strains resistant to three quinolones were isolated from genitourinary secretions. The DNA helicase gene sequences were detected by PCR. Compared with the quinolone-sensitive standard strains ATCC23114 and wild type Strain PG21 gene sequence comparison, analysis of MH DNA helicase II conserved region mutation sites and resistant quinolones relationship. Results Compared with the wild strain (PG21), all the 7 Mh strains resistant to sparfloxacin detected the mutation of S153 → L of GyrA amino acid residues, corresponding to E. coli S83 → L, and the strain 4 also detected the corresponding Escherichia coli S56 → I mutation. Mutants of amino acid residues in GyrA were not found in the Mh strains and standard strains that were sensitive to sparfloxacin. Conclusion The Mh strain GyrA gene encodes a mutation corresponding to Escherichia coli S83 → L amino acid residues associated with Mh anti-sparfloxacin.