Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan.
Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan; German Nepal Tuberculosis Project, Nepal Anti-Tuberculosis Association/GENETUP, Kalimati, Kathmandu, Nepal.
Int J Infect Dis. 2017 Oct;63:13-20. doi: 10.1016/j.ijid.2017.06.010. Epub 2017 Jun 13.
Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) poses a major public health problem in Nepal. Although it has been reported as one of the dominant genotypes of MTB in Nepal, little information on the Central Asian Strain (CAS) family is available, especially isolates related to multidrug resistance (MDR) cases. This study aimed to elucidate the genetic and epidemiological characteristics of MDR CAS isolates in Nepal.
A total of 145 MDR CAS isolates collected in Nepal from 2008 to 2013 were characterized by spoligotyping, mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis, and drug resistance-associated gene sequencing.
Spoligotyping analysis showed CAS1_Delhi SIT26 as predominant (60/145, 41.4%). However, by combining spoligotyping and MIRU-VNTR typing, it was possible to successfully discriminate all 145 isolates into 116 different types including 18 clusters with 47 isolates (clustering rate 32.4%). About a half of these clustered isolates shared the same genetic and geographical characteristics with other isolates in each cluster, and some of them shared rare point mutations in rpoB that are thought to be associated with rifampicin resistance.
Although the data obtained show little evidence that large outbreaks of MDR-TB caused by the CAS family have occurred in Nepal, they strongly suggest several MDR-MTB transmission cases.
结核分枝杆菌（MTB）引起的结核病在尼泊尔构成了一个主要的公共卫生问题。尽管它已被报道为尼泊尔 MTB 的主要基因型之一，但有关中亚株（CAS）家族的信息很少，特别是与耐多药（MDR）病例相关的分离株。本研究旨在阐明尼泊尔 MDR-CAS 分离株的遗传和流行病学特征。
对 2008 年至 2013 年在尼泊尔收集的 145 株 MDR-CAS 分离株进行 spoligotyping、分枝杆菌插入重复单元-可变数串联重复（MIRU-VNTR）分析和耐药相关基因测序。
spoligotyping 分析显示 CAS1_Delhi SIT26 为主导（60/145，41.4%）。然而，通过 spoligotyping 和 MIRU-VNTR 分型相结合，可以成功地将 145 株分离株分为 116 种不同类型，包括 18 个簇 47 株（聚类率 32.4%）。这些聚类分离株中的一半左右与每个簇中的其他分离株具有相同的遗传和地理特征，其中一些分离株在 rpoB 中具有罕见的点突变，这些突变被认为与利福平耐药有关。
尽管所获得的数据表明尼泊尔没有发生由 CAS 家族引起的大规模 MDR-TB 暴发，但强烈提示存在几例 MDR-MTB 传播病例。
