Genetic diversity of Mycobacterium tuberculosis Central Asian Strain isolates from Nepal and comparison with neighboring countries

Yogendra Shah, Ajay Poudel, Bhagwan Maharjan, Jeewan Thapa, Tomoyuki Yamaguchi, Hassan Mahmoud Diab, Basu Dev Pandey, Eddie Solo, Norikazu Isoda, Yasuhiko Suzuki, Chie Nakajima

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Background Multidrug-resistant tuberculosis (MDR-TB) is an emerging threat for successful tuberculosis control worldwide. Central Asian Strain (CAS) has been reported as one of the dominant families contributing to MDR-TB in South Asia including Nepal, India and Pakistan. The aim of this study was to better understand the genetic characteristics of MDR-TB CAS family isolates circulating in Nepal and compare the results with neighboring countries. Methods A total of 145 MDR-TB CAS family isolates collected in Nepal from 2008 to 2013 were analyzed by spoligotyping and mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) analysis. In addition, we compared these data with published data from India and Pakistan to investigate a possible epidemiological link via construction of a minimum spanning tree (MST). Results Spoligotyping analysis exhibited CAS1-Delhi SIT26 (n=60) as the predominant lineage among the MDR-TB CAS family in all three countries. However, the combined analysis with spoligotyping and MIRU-VNTR further discriminated 60 isolates into 49 different types and 5 clusters. Each cluster was composed of 14 isolates with a clustering rate of 23.3%, suggesting ongoing transmissions. Based on MST data from neighboring countries, we elucidated an evolutionary relationship between the two countries, Nepal and India, which could be explained by their open border. Conclusion This study identified the evolutionary relationships among MDR-TB CAS1-Delhi subfamily isolates from Nepal and those from neighboring countries.

Original languageEnglish
Pages (from-to)203-211
Number of pages9
JournalTransactions of the Royal Society of Tropical Medicine and Hygiene
Issue number4
Publication statusPublished - Apr 1 2019
Externally publishedYes


  • CAS1-Delhi
  • MST
  • multidrug-resistant TB
  • Nepal

ASJC Scopus subject areas

  • Parasitology
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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