Yogendra Shah1, Ajay Poudel2, Bhagwan Maharjan3,4, Jeewan Thapa4, Tomoyuki Yamaguchi4, Hassan Mahmoud Diab5, Basu Dev Pandey6,7, Eddie Solo4,8, Norikazu Isoda4,9, Yasuhiko Suzuki4,9, Chie Nakajima4,9. 1. National Zoonoses and Food Hygiene Research Centre, Kathmandu, Nepal. 2. Chitwan Medical College and Teaching Hospital, Department of Microbiology, Bharatpur, Chitwan, Nepal. 3. German Nepal Tuberculosis Project, Nepal anti-Tuberculosis association/GENETUP, Kalimati, Kathmandu, Nepal. 4. Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan. 5. Department of Animal Hygiene, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt. 6. Sukraraj Tropical and Infectious Disease Hospital, Teku, Kathmandu, Nepal. 7. Everest International Clinic and Research Center, Kathmandu, Nepal. 8. University Teaching Hospital, Lusaka, Zambia. 9. Hokkaido University, GI-CoRE Global Station for Zoonosis Control, Sapporo, Japan.
Abstract
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.
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.