Kekkaku : [Tuberculosis]
-
Before the availability of high-resolution genotyping tools in 1990s, there was a prevailing dogma of little genomic sequence diversity in Mycobacterium tuberculosis. Due to the low levels of genetic variation, it was assumed that M. tuberculosis exhibit very little phenotypic variation in immunologic and virulence factors. The fingerprinting method based on restriction fragment length polymorphisms (RFLP) of IS6110 insertion sequences had unveiled the underestimation of the sequence variation in M. tuberculosis and the importance of strain-to-strain variation for understanding pathogenesis, immune mechanisms, bacterial evolution, and host adaptation. ⋯ The other example we showed: we can know relapse, reinfection, or laboratory contamination by using VNTR in a few days when a patient shows bacteriological relapse during the treatment. By introducing VNTR to clinical practice, we can diminish days of inappropriate hospitalization. Because VNTR data are numerical, we can easily construct VNTR database, compare data, and survey emergence of MDR/XDR-tuberculosis.
-
Kekkaku : [Tuberculosis] · Dec 2009
[Population structure analysis of Mycobacterium tuberculosis Beijing family in Japan].
The Beijing family is a genotypic lineage of M. tuberculosis that reportedly predominates throughout eastern Asia and in parts of Russia yet dispersed worldwide. About 80% of clinical isolates in Japan are belonging to this family. The predominance of a narrow range of genotypes, in this case predominance by Beijing family strains, hypothesized that these strains may have a selective advantage either with virulence or transmissibility that led to clonal expansion. ⋯ In the combination of molecular epidemiological data with recent advances in mycobacterial genomics and population genetics, we could provide novel insights into genetic diversity and phylogeny of M. tuberculosis Beijing family strains circulating in Japan. This would be a good start to approaching the genetic determinants causing variations in virulence and transmissibility of M. tuberculosis. We are currently applying the next-generation sequencing technology to get the whole genome sequencing of the representative strains from each monophyletic subgroup within M. tuberculosis Beijing family.