title: Characterization of predominant Mycobacterium tuberculosis strains from different subpopulations of India.
abstract: The predominant strains from India belong to Central-Asian (CAS) and the East-African-Indian (EAI) clade of Mycobacterium tuberculosis. The two clades have also been shown to be geographically partitioned. The study of such strains may help to understand the characteristics that make M. tuberculosis an effective pathogen and its overrepresentation in certain populations. M. tuberculosis isolates characterized by spoligotyping under a population based tuberculosis study covering different regions from the North and South India were further analyzed by restriction fragment length polymorphism (RFLP) and by deletion analysis of M. tuberculosis specific deletion region 1 (TbD1). The genetic relationship of the two clades inferred using different genetic markers showed good correlation. In the North where the CAS clade predominates the isolates are characterized by presence of high IS6110 copy number and absence of TbD1 region whereas in the South where the EAI clade predominates the isolates are characterized by low copy number of IS6110 and presence of TbD1 region. The ancestral EAI strains were found to be less often associated with drug resistance or young age as compared to the CAS clade. The study highlights that the EAI lineage is well established in India and that CAS may be emerging or more recently introduced to India. The results depict a distinction in the lineage of strains from the North versus South India indicating a need to study if the pathogen has adapted to specific human populations.
authors.affiliation: Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Arora
authors.forename: Urvashi Balbir
authors.initials: UB
authors.lastname: Singh
authors.forename: Naga
authors.initials: N
authors.lastname: Suresh
authors.forename: Tanu
authors.initials: T
authors.lastname: Rana
authors.forename: Chhavi
authors.initials: C
authors.lastname: Porwal
authors.forename: Amit
authors.initials: A
authors.lastname: Kaushik
authors.forename: Jitendra Nath
authors.initials: JN
authors.lastname: Pande
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA / Q000379:methods; D014376:Tuberculosis / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission