Habitat and Morphology of Mycobacterium tuberculosis

 

Habitat

1. Human is only the know reservoir.
2. Usually found in the lungs but can also live in any part of the body.
3. They may be obligate pathogen, facultative or opportunistic pathogens or free living.
4. Usually infect the mono-nuclear phagocytes.
5. Can also be infected by the consumption of unpasteurized milk.
6. Can survive for weeks in dust, on carpets or clothes, for months in sputum.
7. They are also found in soil and water.

Morphology

1. Straight or slightly curved thin rod shaped bacilli
2. Non-sporing, non-motile, non-capsulated bacteria.
3. Acid fast bacilli, neither gram +ve nor gram –ve.
4. During acid fast stain, they appear bright red to intensive purple with green/blue background.
5. They measure 0.5 µm x 3 µm.
6. Appears in single, in pairs or small chumps.
7. High content of mycolic acid (50 to 60 %).
8. Cell wall is rich in lipids and waxes.
9. They are wrapped together due to presence of fatty acids.
10. Capable of intracellular growth.
11. They are resistance to disinfectants, detergents, common antibiotics, dyes, stains, osmotic lysis, lethal oxidation, etc.

Habitat and Morphology of Mycobacterium tuberculosis