Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China; National Centre for STD and Leprosy Control, China CDC, Nanjing, China; Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.
Yunnan Provincial CDC, Kunming, China.
Int J Infect Dis. 2020 Sep;98:6-13. doi: 10.1016/j.ijid.2020.06.032. Epub 2020 Jun 14.
Understanding the nature of Mycobacterium leprae transmission is vital to implement better control strategies for leprosy elimination. The present study expands the knowledge of county-level strain diversity, distribution, and transmission patterns of leprosy in endemic provinces of China.
We genetically characterized 290 clinical isolates of M. leprae from four endemic provinces using variable number tandem repeats (VNTR) and single nucleotide polymorphisms (SNPs). Attained genetic profiles and cluster consequences were contrasted with geographical and migration features of leprosy at county levels.
Considering the allelic variability of 17 VNTR loci by the discriminatory index, (GTA)9, (AT)17, (AT)15, (TA)18, (TTC)21, and (TA)10 are reported to be more highly polymorphic than other loci. The VNTR profile generated the low-density clustering pattern in the counties of Sichuan and Yunnan, whereas clusters have been observed from the isolates from Huayuan (N = 6), Yongding (N = 3), Zixing (N = 3), Chenxi (N = 2) and Zhongfang (N = 2) counties of Hunan, and Zhijin (N = 3), Anlong (N = 2), Zhenning (N = 2), and Xixiu (N = 2) counties of Guizhou. In some clusters, people's social relations have been observed between villages. From the 290 clinical isolates, the most predominantly reported SNP was 3K (278, 95.8%), followed by SNP 1D (10, 3.4%), which are typically observed to be predominant in China. We also detected the novel SNP 3J (2, 0.8%), which has not yet been reported in China.
The clustering pattern of M. leprae indicates the transmission of leprosy still persists at county levels, suggesting that there is a need to implement better approaches for tracing the close contacts of leprosy patients.
了解麻风分枝杆菌传播的性质对于实施更好的麻风消除控制策略至关重要。本研究扩展了中国流行省份麻风病县级菌株多样性、分布和传播模式的知识。
我们使用可变数串联重复（VNTR）和单核苷酸多态性（SNP）对来自四个流行省份的 290 株临床麻风分枝杆菌分离株进行基因特征分析。获得的遗传谱和聚类结果与县级麻风病的地理和迁徙特征进行了对比。
考虑到 17 个 VNTR 位点的等位基因变异性，通过鉴别指数（GTA）9、（AT）17、（AT）15、（TA）18、（TTC）21 和（TA）10 被报道比其他位点具有更高的多态性。VNTR 谱在四川和云南的县中产生了低密度聚类模式，而在湖南的花园（N=6）、永定（N=3）、资兴（N=3）、辰溪（N=2）和中方（N=2）以及贵州的织金（N=3）、安龙（N=2）、镇宁（N=2）和西秀（N=2）县的分离株中观察到了聚类。在一些聚类中，人们之间观察到了村庄之间的社会关系。在 290 株临床分离株中，报告最多的 SNP 是 3K（278，95.8%），其次是 SNP 1D（10，3.4%），这在中国通常是主要的。我们还检测到了尚未在中国报道的新型 SNP 3J（2，0.8%）。
麻风分枝杆菌的聚类模式表明麻风病的传播仍在县级层面持续，这表明需要实施更好的方法来追踪麻风病患者的密切接触者。
