The full name of NTM is non-tuberculous mycobacteria, mycobacteria are rod-shaped bacteria, and mycobacteria that grow in a branched form are mycobacteria, such as Mycobacterium tuberculosis, which causes people to get tuberculosis, is a kind of mycobacteria, and the bacteria that causes people to get leprosy is also a kind of mycobacteria, also called Mycobacterium leprae. In addition to Mycobacterium tuberculosis and Mycobacterium leprae, there are many other mycobacteria, which are commonly known as nontuberculous mycobacteria. Non-tuberculous mycobacteria are widely found in nature, such as in soil, dust, water, poultry, and fish, therefore, they are also called environmental mycobacteria, and some non-tuberculous mycobacteria also live in the respiratory tract of healthy people. Non-tuberculous mycobacteria are less pathogenic to humans than Mycobacterium tuberculosis, and when the resistance of a person decreases these bacteria will invade the body and cause a person to get sick, also known as non-tuberculous mycobacteriosis, and non-tuberculous mycobacteria mainly invade the lungs of a person, also known as NTM lung disease.