Mycobacterium is a genus of bacteria that includes the species that cause tuberculosis (TB) and leprosy. It contains obligate parasites like Mycobacterium tuberculosis and M. leprae, which cause diseases, as well as opportunistic pathogens like non-tuberculous mycobacteria. Mycobacterium species are acid-fast bacilli with a cell wall rich in lipids, making them resistant to disinfectants and host immune responses. They can survive outside of hosts for weeks. M. tuberculosis was discovered in 1882 and is the main cause of TB, appearing as thin rods in tissue.

1. Mycobacterium
species
BY HABTAMU BIAZIN

2. Mycobacterium species
• Mycobacterium is a genus within the order of
actinomycetal.
• It compromises a large number of well characterized
species.
• Several of which are associated with human and
animal diseases such as TB and leprosy.
• The genus Mycobacterium contains three groups.

3. Mycobacterium species …
• Obligate parasites: this includes
• 1. Mycobacterium Tuberculosis Complex(MTC):
• M. tuberculosis, M. bovis, M.africanum, M. canetti, M.microti,
M.caprae, M. pinnipeddi
• 2. Mycobacterium leprae
• Opportunistic pathogens
• These are the nontuberculosis Mycobacterium (NTM)
• they are categorized as
• Photochromogens

4. Mycobacterium species …
• Scotochromogen, Non-chromogens AND Rapid Growers
This is the traditional Runyon classification
1. tuberculosis
complex
M. tuberculosis M. bovis M.africanum
M. leprae
2. Photochromogens M. kansassi , M. marinum
3. Scotochromogen M. scrofulaceum, M. gordonae, M. szulgai
4. Non-chromogens M. avium-intracellulare, M. xenopi, M. terrae
5. Rapid growers M. fortuitum, M. abscessus, M. chelonae, M. Smegmatis

5. Mycobacterium species
• Saprophytes:
• are isolated from may sources
• These includes: M. phlei (grass) and M. Smegmatis
(smegma)

6. GENERAL PROPERTIES
• Mycobacteria are Slender Rods
• They sometimes show branching, filamentous forms resembling
with fungi mycelium.
• They are aerobic, non motile, non capsulated and non spore
forming
• usually having slow growth
• They are acid fast bacilli (AFB)
• Cell wall- rich in lipids

7. Mycobacterium Tuberculosis
• The bacterium that causes Tuberculosis.
• TB also caused by M.bovis
• M.tuberculosis was discovered in 1882 by Robert Koch
• Morphology
• In tissue
• Mtb is a thin, straight or slightly curved rod(0.4× 3 µm) where as
M.bovis is straight rod and short (0.3×3 µm).

8. Morphology…
• On artificial media:
• Filamentous forms are seen with variable morphology from one
species to the an other.
• They occur singly, in pairs or as a small clumps.
Mtb on LJ medium

9. Morphology …
• They are obligate aerobic, non motile, non capsulated and non spore
forming.
• They are alcohol and acid fast.
• Slow growing ( doubling time 18hrs)
• cell wall: rigid, rich in lipids, hydrophobic, resistant to many
disinfectants, detergents, stains, antibiotics and host immune
responses.

10. Property… Resistance
• Relatively resistance acid and alkali
• 5% phenol, 15% H2 SO4, 3% nitric acid, 4% NaOH
• Resistance to dehydration:
• can survive
• expectorated sputum for 20-30 hrs and
• in droplet nuclei for 8-10 days.
• which is important for transmission by aerosols.

11. Property… Resistance
• Destroyed by 80% ethanol for 2 minutes and 5
minutes iodine solution.
• Sensitive to formaldehyde, glutaraldehyde
• Killed at 60℃ 𝑓𝑜𝑟 10 − 15 𝑚𝑖𝑛𝑢𝑡𝑒𝑠
• Culture may be killed by direct sunlight for 2hrs.

13. • Thank you for your attention!!!!