Thick and wrinkled pellicle production on Sauton
medium surface
Colonies on Lowenstein-Jensen medium
(M. bovis old culture)
Mycobacterium cells forming cords
(Ziehl-Neelsen staining)
Produces tuberculosis in man and animals.
Experimentally, from an inoculum of 0.01 mg,
Mycobacterium tuberculosis is highly
pathogenic for guinea pigs and hamsters, but relatively non-pathogenic for bovines,
cats, domestic fowls, goats, and rabbits. Inocula of 0.001-1 mg produce experimental
disease in mice.
Infected animals, including man, exhibit delayed hypersensitivity to crude or purified
Mycobacterium tuberculosis culture filtrates (tuberculins) and less sensitivity to
tuberculin-like preparations from other mycobacteria. Disease caused by
Mycobacterium bovis cannot be distinguished from that due to Mycobacterium
by use of commonly available tuberculins.

Bacillus Calmette-Guérin (BCG) is a live attenuated
Mycobacterium bovis strain used
to prevent tuberculosis and other mycobacterial infections. The vaccine was
developed by Calmette and Guérin and was first administered to human beings in
1921. BCG is the only vaccine against tuberculosis.

"Mycobacterium orygis" is causative agents of tuberculosis in the animal species.
Recently it was reported as a cause of human tuberculosis in patients of South Asian
Mycobacterium tuberculosis
Cultural characteristics
Biochemical characters
Phylum Actinobacteria, Class Actinobacteria, Order Actinomycetales, Suborder Corynebacterineae, Family Mycobacteriaceae, Genus
Mycobacterium tuberculosis (Zopf 1883) Lehmann and Neumann 1896, type species of the genus.

Old synonyms: "Bacterium tuberculosis" Zopf 1883, "Bacillus tuberculosis" (Zopf 1883) Klein 1884, "Mycobacterium tuberculosis
typus humanus" Lehmann and Neumann 1907, "Mycobacterium tuberculosis var. hominis" Bergey et al. 1934.

Mycobacterium tuberculosis complex comprises Mycobacterium tuberculosis, M. africanum, M. canettii, M. bovis, M. microti, M. orygis,
M. caprae, M. pinnipedii, M. suricattae,  M. mungi, M. dassie,
and M. oryx.
According to Riojas et al. (2018), “phylogenomic analysis of the species of the Mycobacterium tuberculosis complex demonstrates
M. africanum, M. bovis, M. caprae, M. microti and M. pinnipedii are later heterotypic synonyms of Mycobacterium tuberculosis”.

"Mycobacterium canetii" does not differ from
Mycobacteriurn tuberculosis in the biochemical tests and in its 16s rRNA sequence, but
produce smooth and glossy colonies.
According to Jakko van Ingen et al. the "oryx bacillus" is a phylogenetically distinct lineage of the clonal
M. tuberculosis complex and
thus deserves a separate subspecies status as
Mycobacterium orygis.
Acid-alcohol-fast, straight or slightly curved rods, 0.3-0.6 / 1-4 μm, occurring singly
and in occasional threads. Generation time in vitro under optimal conditions is 14-15
hours. Most strains can produce cords, a virulence-related character.
Colonies are rough, raised, and thick, with a nodular or wrinkled surface and an
irregular thin margin; may become somewhat pigmented (off-white to faint buff, or
even yellow). Colonies on oleic acid-albumin agar are flat, rough, corded, dry, and
usually non-pigmented. In liquid media, old cultures produce a thick and wrinkled
pellicle. Grows on Lowenstein-Jensen with glycerol or sodium piruvate. No growth in
5% NaCl. No growth on MacConkey agar.
Optimum temperature for growth is 37 ºC (some growth occurs at 30-34 ºC).
Optimum pH is 6.4-7.0. Growth is stimulated by adding  5-10% CO
2, and 0.5% (w/v)
Isolated from cases of tuberculosis in man, other primates, dogs and other animals
which have contact with man. Resistant to thiophene-2-carboxylic acid hydrazide
(TCH). Sensitive to rifampin (25 μg/ml), hydroxylamine (500 µg/ml), ethambutol (2
µg/ml) and isoniazid (1 µg/ml). Variable resistance to streptomycin.
"Mycobacterium canetii" was isolated from a 2-year-old Somali patient with
"Mycobacterium orygis" havs been isolated from members of the Bovidae family,
(oryxes, gazelles, deer, antelope, and waterbucks), although their exact host range
remains unsettled.
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  4. Marco A. Riojas, Katya J. McGough, Cristin J. Rider-Riojas, Nalin Rastogi and Manzour Hernando Hazbón. Phylogenomic analysis
    of the species of the Mycobacterium tuberculosis complex demonstrates that Mycobacterium africanum, Mycobacterium bovis,
    Mycobacterium caprae, Mycobacterium microti and Mycobacterium pinnipedii are later heterotypic synonyms of Mycobacterium
    tuberculosis. Int J Syst Evol Microbiol. 2018 Jan;68(1):324-332. doi: 10.1099/ijsem.0.002507.
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Positive results for acid phosphatase, alpha-esterase, niacin production
(niacin-negative strains may be found in patients who have
received long-term chemotherapy), nitrate reduction, nicotinamidase,
pyrazinamidase, Tween 80 hydrolysis (most strains) and urease.

Negative results for catalase (inactivated at 68 ºC), semiquantitative catalase test,
arylsulphatase (3 and 10 days), beta-galactosidase, iron uptake, and tellurite
reduction (variable / positive at 9 days strains).
No utilization as sole carbon source of acetate, citrate, succinate, malate, pyruvate,
benzoate, fumarate, glucose, fructose, sucrose ethanol, and propanol.
(c) Costin Stoica
Culture media
Biochemical tests
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