Yih-Yuan Chen1, Jia-Ru Chang2, Wei-Feng Huang2, Chih-Hao Hsu2, Han-Yin Cheng2, Jun-Ren Sun3, Shu-Chen Kuo2, Ih-Jen Su2, Ming-Shian Lin4, Wei Chen4, Horng-Yunn Dou5. 1. National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, Taiwan, ROC; Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan, ROC. Electronic address: yihyuan.chen@msa.hinet.net. 2. National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, Taiwan, ROC. 3. Division of Clinical Pathology, Department of Pathology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan, ROC. 4. Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan, ROC. 5. National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, Taiwan, ROC. Electronic address: hydou@nhri.org.tw.
Abstract
BACKGROUND: The Beijing lineage of Mycobacterium tuberculosis (MTB) is the most predominant MTB strain in Asian countries and is spreading worldwide, however, the East African-Indian (EAI) lineage is also particularly prevalent in many tropical Asian countries. The evolutionary relationships among MTB EAI isolates from Taiwan and those of tropical Asian countries remain unknown. METHODS: The EAI strains collected from patients in Taiwan were analyzed using spacer oligonucleotide typing and mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) typing, and compared with published profiles from Cambodia and Singapore to investigate potential epidemiological linkages. RESULTS: Among the three countries, the EAI lineage was most prevalent in Cambodia (60%; Singapore, 25.62%; and Taiwan, 21.85%), having also the highest rates of multidrug resistance and lowest rates of clustering of MTB isolates. We describe a convenient method using seven selected MIRU-VNTR loci for first-line typing to discriminate Beijing and EAI lineages. A potential epidemiological linkage in these tropical Asian countries is also discussed based on a minimum-spanning tree constructed using 24 MIRU-VNTR loci of MTB EAI strains. CONCLUSION: This study identified evolutionary relationships among MTB EAI isolates from Taiwan and those of two other tropical Asian countries, Cambodia and Singapore.
BACKGROUND: The Beijing lineage of Mycobacterium tuberculosis (MTB) is the most predominant MTB strain in Asian countries and is spreading worldwide, however, the East African-Indian (EAI) lineage is also particularly prevalent in many tropical Asian countries. The evolutionary relationships among MTB EAI isolates from Taiwan and those of tropical Asian countries remain unknown. METHODS: The EAI strains collected from patients in Taiwan were analyzed using spacer oligonucleotide typing and mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) typing, and compared with published profiles from Cambodia and Singapore to investigate potential epidemiological linkages. RESULTS: Among the three countries, the EAI lineage was most prevalent in Cambodia (60%; Singapore, 25.62%; and Taiwan, 21.85%), having also the highest rates of multidrug resistance and lowest rates of clustering of MTB isolates. We describe a convenient method using seven selected MIRU-VNTR loci for first-line typing to discriminate Beijing and EAI lineages. A potential epidemiological linkage in these tropical Asian countries is also discussed based on a minimum-spanning tree constructed using 24 MIRU-VNTR loci of MTB EAI strains. CONCLUSION: This study identified evolutionary relationships among MTB EAI isolates from Taiwan and those of two other tropical Asian countries, Cambodia and Singapore.