Humans are the only reservoir for the bacterium.Mycobacterium tuberculosis is an obligate aerobe.
For this reason, in the classic case of tuberculosis, the M.TB. complexes are always found in the
well-aerated upper lobes of the lungs. The bacterium is a facultative intracellular parasite,
usually of macrophages, and has a slow generation time, 15-20 hours, a physiological characteristic that may contribute to its virulence.
The cell wall structure of Mycobacterium tuberculosis deserves special attention because it is unique among procaryotes and it is a major determinant of virulence for the bacterium.
The cell wall complex contains peptidoglycan, but otherwise it is composed of complex lipids. Over 60% of the mycobacterial cell wall is lipid.
The Disease Tuberculosis
TB infection means that M.TB. is in the body but the immune system is keeping the bacteria under control. The immune system does this by producing
macrophages that surround the tubercle bacilli. The cells form a hard shell that keeps the bacilli contained and under control. Most people with
TB infection have a positive reaction to the tuberculin skin test. People who have TB infection but not TB disease are NOT infectious, i.e., they
cannot spread the infection to other people.
Additional information can be found hereProteom analysis(Russian)and here Tuberculosis