Mycobacterium tuberculosis is a slender and slightly curved bacterium, which is arranged in a single or branched manner without flagella and spores. Size (1 ~ 4) μ m× 0.4 μ m. Mycobacterium bovis is thicker and shorter. In the old lesions and cultures, the morphology is often atypical, which can be granular, spherical, short rod-shaped, filamentous and so on. In recent years, it has been found that Mycobacterium tuberculosis has a coating outside the cell wall, which has a certain protective effect on Mycobacterium tuberculosis.
Specific aerobic capacity of mycobacterium tuberculosis. The optimum temperature is 37℃ and the optimum pH is 6.5 ~ 6.8. Growth is slow, and colonies visible to the naked eye appear after 3 ~ 4 weeks of inoculation and culture. The most remarkable feature of this genus is that the cell wall contains a lot of lipids, so it grows and forms rough hydrophobic colonies.