杭州地区结核分枝杆菌氧氟沙星耐药株的MIRU-VNTR基因分型研究

The genotyping of ofloxacin-resistant mycobacterium tuberculosis with MIRU-VNTR in Hangzhou city

目的探讨MIRU-VNTR技术在杭州地区结核分枝杆菌氧氟沙星耐药株基因分型中的应用。方法收集杭州市2010年4月—2012年6月各结核病定点医院分离培养的临床菌株,进行药物敏感性检测。分别采用RD105缺失基因检测法和MIRU-VNTR技术对氧氟沙星耐药株进行菌株鉴定和基因分型。结果筛选出的52株氧氟沙星耐药株中,43株(82.69%)为北京家族菌株。经12个MIRU-VNTR位点组合分析,52株氧氟沙星耐药株呈52种MIRU-VNTR基因型,总Hunter-Gaston指数(HGI)为0.999。除MIRU40和ETR-F外,其他10个MIRU-VNTR位点对北京家族菌株和非北京家族菌株均显示较高或中等程度的分辨率。结论筛选到的10个MIRU-VNTR位点具有较高分辨率,适用于杭州地区结核分枝杆菌氧氟沙星耐药株分型。

Objective To evaluate the application of MIRU - VNTR analysis in genotyping of the ofloxacin - resistant mycobacterium tuberculosis in Hangzhou. Methods From April 2010 to June 2012,the clinical isolates of mycobacterium tuberculosis were collected from designated TB hospitals in Hangzhou for drug sensitivity test. The ofloxacin -resistant mycobacterium tuberculosis strains were typed with RD105 deletion test and MIRU-VNTR typing method respectively,and the results from both methods were compared. Results A total of 52 ofloxacin -resistant mycobacterium tuberculosis strains were collected. Using RD105 deletion test,43 strains（82. 69%）belonged to mycobacterium tuberculosis Beijing family. Using a 12-locus MIRU-VNTR typing,52 distinct MIRU-VNTR patterns were detected in the 52 ofloxacin-resistant strains. The Hunter-Gaston discriminatory index（HGI）was 0. 999. Except MIRU40 and ETR-F,the other 10 MIRU-VNTR loci showed moderate or high discriminatory power for both Beijing genotype isolates and non -Beijing genotype isolates. Conclusion The selected 10 MIRU-VNTR loci has a higher discriminatory power and are appropriate for the ofloxacin-resistant mycobacterium tuberculosis genotyping.