The ''Mycobacterium tuberculosis'' complex (MTC or MTBC) is a genetically related group of ''

Mycobacterium ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

'' species that can cause

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

in humans or other animals. It includes: * ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on its c ...

'' * ''

Mycobacterium africanum ''Mycobacterium africanum'' is a species of ''Mycobacterium'' that is most commonly found in West African countries, where it is estimated to cause up to 40% of pulmonary tuberculosis. The symptoms of infection resemble those of ''M. tuberculosi ...

'' * ''

Mycobacterium orygis ''Mycobacterium orygis'' is a species of the tuberculosis complex of the genus ''Mycobacterium''. It causes tuberculosis in oryx, rhinos, dairy cattle, rhesus monkeys, and humans. Morphology ''Mycobacterium orygis'' is similar in morphology t ...

'' * ''

Mycobacterium bovis ''Mycobacterium bovis'' is a slow-growing (16- to 20-hour generation time) aerobic bacterium and the causative agent of tuberculosis in cattle (known as bovine TB). It is related to ''Mycobacterium tuberculosis'', the bacterium which causes tube ...

and the Bacillus Calmette–Guérin strain'' * ''

Mycobacterium microti ''Mycobacterium microti'' *Member of the Mycobacterium tuberculosis complex (MTBC) *Also known as the 'Vole bacillus' *Etymology: microtus is a genus that includes small field rodents such as the vole. This mycobacterium species was first descri ...

'' * ''

Mycobacterium canetti ''Mycobacterium canettii'', a novel pathogenic taxon of the ''Mycobacterium tuberculosis'' complex (MTBC), was first reported in 1969 by the French microbiologist Georges Canetti, for whom the organism has been named. It formed smooth and shin ...

'' * ''

Mycobacterium caprae ''Mycobacterium caprae'' is a species of bacteria in the genus ''Mycobacterium'' and a member of the Mycobacterium tuberculosis complex. The species is named after the caprines, the organisms from which M. caprae was first isolated. Prior to 200 ...

'' * ''

Mycobacterium pinnipedii ''Mycobacterium pinnipedii'' is a member of the Mycobacterium tuberculosis complex which primarily infects seals. It is a slowly growing Mycobacterium. The species is named after the Pinniped Pinnipeds (pronounced ), commonly known as sea ...

'' * ''

Mycobacterium suricattae ''Mycobacterium suricattae'' is a species of the tuberculosis complex of the genus ''Mycobacterium''. It causes tuberculosis in meerkats, and was first identified from South African animals in 2013. Prior to this, it was considered to be synonymo ...

'' * ''

Mycobacterium mungi ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

'' In addition, two branches exist which have phylogenetic similarities but are not completely described: the dassie and oryx bacilli. Oryx bacilli has been recently reclassified into a separate subspecies, orygis. Members of the MTC can be distinguished from all other bacteria by the presence of 63

conserved signature indels Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers ...

(CSIs) present in diverse proteins that are exclusively shared by these pathogens. Due to their exclusivity for the MTC complex and presence in highly conserved regions of proteins, these CSIs provide novel means for functional and diagnostic studies (including potential targets for development of novel therapeutics).

Phylogenetics

As MTBC diverged into different lineages, so did the expression of key and metabolic pathogenic genes, as a result of mutations introducing new TANNNT Pribnow boxes and mutations that impair the function of repressors Transcripcionales. This provides clear evidence that MTBC lineages probably reflect adaptation to different human populations. In fact, modifying gene expression could be a rapid mechanism for physiological adaptation to a new environment without the need to substantially change the genome. This can be seen reflected in the way that the different MTBC clades have their own transcriptomic signature. Even single-point mutations can completely change the transcriptional profile of a strain. An example is the N1177 strain, which carries a single mutation in the rpoB gene that confers resistance to rifampicin that modified transcription levels of multiple genes. The role of methylation is more elusive, the mutation inactivation pattern seems to confirm that methylases are not preserved throughout mtBC. Transcriptional adaptation can allow M. tuberculosis isolates to optimize their infectivity and transmission in subtly different environments provided by different human host populations. CC-BY icon

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References

tuberculosis complex The ''Mycobacterium tuberculosis'' complex (MTC or MTBC) is a genetically related group of ''Mycobacterium'' species that can cause tuberculosis in humans or other animals. It includes: * ''Mycobacterium tuberculosis'' * ''Mycobacterium africanu ...

Tuberculosis {{Mycobacterium-stub

Phylogenetics

See also

References