Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
Shenzhen Center for Chronic Disease Control, Shenzhen, China.
Nat Ecol Evol. 2018 Dec;2(12):1982-1992. doi: 10.1038/s41559-018-0680-6. Epub 2018 Nov 5.
A small number of high-burden countries account for the majority of tuberculosis cases worldwide. Detailed data are lacking from these regions. To explore the evolutionary history of Mycobacterium tuberculosis in China-the country with the third highest tuberculosis burden-we analysed a countrywide collection of 4,578 isolates. Little genetic diversity was detected, with 99.4% of the bacterial population belonging to lineage 2 and three sublineages of lineage 4. The deeply rooted phylogenetic positions and geographic restriction of these four genotypes indicate that their populations expanded in situ following a small number of introductions to China. Coalescent analyses suggest that these bacterial subpopulations emerged in China around 1,000 years ago, and expanded in parallel from the twelfth century onwards, and that the whole population peaked in the late eighteenth century. More recently, sublineage L2.3, which is indigenous to China and exhibited relatively high transmissibility and extensive global dissemination, came to dominate the population dynamics of M. tuberculosis in China. Our results indicate that historical expansion of four M. tuberculosis strains shaped the current tuberculosis epidemic in China, and highlight the long-term genetic continuity of the indigenous M. tuberculosis population.
少数高负担国家占全球结核病病例的大多数。这些地区缺乏详细数据。为了探索中国（结核病负担第三高的国家）结核分枝杆菌的进化历史，我们分析了全国范围内采集的 4578 株分离株。检测到的遗传多样性很小，细菌种群的 99.4%属于谱系 2 和谱系 4 的三个亚谱系。这四个基因型根深蒂固的系统发育位置和地理限制表明，它们的种群是在少数几次引入中国后在当地扩张的。合并分析表明，这些细菌亚群大约在 1000 年前在中国出现，并从 12 世纪开始平行扩张，整个种群在 18 世纪末达到顶峰。最近，起源于中国的、具有相对较高传播性和广泛全球传播性的 L2.3 亚谱系，开始主导中国结核分枝杆菌种群的动态。我们的研究结果表明，四种结核分枝杆菌菌株的历史扩张塑造了中国当前的结核病流行，突显了本土结核分枝杆菌种群的长期遗传连续性。
