Mycobacterium tuberculosis is the etiologic agent of tuberculosis. Mycobacterium tuberculosis can invade all organs of the body, but pulmonary tuberculosis is the most common, as follows: 1. Mycobacterium tuberculosis is sensitive to ethanol and dies in two minutes in 70% ethanol. 2. Mycobacterium tuberculosis is particularly resistant to drying, adheres to dust to remain infectious for 8-10 days, and can survive in dry sputum for 6-8 months. 3, Mycobacterium tuberculosis is sensitive to moist heat and is killed by heating in liquid at 62-63°C for 15 minutes or by boiling. 4. Mycobacterium tuberculosis is sensitive to ultraviolet light and can be killed by direct sunlight for several hours and can be used to disinfect clothes and books of tuberculosis patients.