Zheng Chao, Zhao Yuding, Zhu Guoqiang, Li Song, Sun Honghu, Feng Qin, Luo Mei, Wu Fanzi, Li Xuefeng, Hill Véronique, Rastogi Nalin, Sun Qun
Key Laboratory of Bio-Resources and Eco-Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China.
Key Laboratory of Bio-Resources and Eco-Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China ; Chengdu Longquan Health School, Chengdu, Sichuan 610100, China.
Biomed Res Int. 2014;2014:763204. doi: 10.1155/2014/763204. Epub 2014 Mar 3.
Genotypes of Mycobacterium tuberculosis complex (MTBC) vary with the geographic origin of the patients and can affect tuberculosis (TB) transmission. This study was aimed to further differentiate spoligotype-defined clusters of drug-resistant MTBC clinical isolates split in Beijing (n = 190) versus non-Beijing isolates (n = 84) from Sichuan region, the second high-burden province in China, by IS6110-restriction fragment length polymorphism (RFLP) and 24-locus MIRU-VNTRs. Among 274 spoligotyped isolates, the clustering ratio of Beijing family was 5.3% by 24-locus MIRU-VNTRs versus 2.1% by IS6110-RFLP, while none of the non-Beijing isolates were clustered by 24-locus MIRU-VNTRs versus 9.5% by IS6110-RFLP. Hence, neither the 24-locus MIRU-VNTR was sufficient enough to fully discriminate the Beijing family, nor the IS6110-RFLP for the non-Beijing isolates. A region adjusted scheme combining 12 highly discriminatory VNTR loci with IS6110-RFLP was a better alternative for typing Beijing strains in Sichuan than 24-locus MIRU-VNTRs alone. IS6110-RFLP was for the first time introduced to systematically genotype MTBC in Sichuan and we conclude that the region-adjusted scheme of 12 highly discriminative VNTRs might be a suitable alternative to 24-locus MIRU-VNTR scheme for non-Beijing strains, while the clusters of the Beijing isolates should be further subtyped using IS6110-RFLP for optimal discrimination.
结核分枝杆菌复合群（MTBC）的基因型因患者的地理来源而异，并可影响结核病（TB）的传播。本研究旨在通过IS6110限制性片段长度多态性（RFLP）和24位点MIRU-VNTRs，进一步区分来自中国第二高负担省份四川地区的耐多药MTBC临床分离株中，北京株（n = 190）与非北京株（n = 84）的间隔寡核苷酸分型（spoligotype）定义的簇。在274株经spoligotype分型的分离株中，24位点MIRU-VNTRs显示北京家族的聚类率为5.3%，而IS6110-RFLP为2.1%；非北京株分离株中，24位点MIRU-VNTRs未显示聚类，而IS6110-RFLP为9.5%。因此，24位点MIRU-VNTR不足以完全区分北京家族，IS6110-RFLP也不足以区分非北京株。对于四川地区的北京株分型，将12个高分辨率VNTR位点与IS6110-RFLP相结合的区域调整方案比单独使用24位点MIRU-VNTRs更好。IS6110-RFLP首次被引入用于对四川地区的MTBC进行系统基因分型，我们得出结论，对于非北京株，12个高分辨率VNTRs的区域调整方案可能是24位点MIRU-VNTR方案的合适替代方案，而北京株分离株的簇应进一步使用IS6110-RFLP进行亚型分析以实现最佳区分。
