Nontuberculous mycobacteria (NTM) refer to mycobacteria in the genus Mycobacterium, except for the Mycobacterium tuberculosis complex (human, bovine, African and voles tuberculosis) and Mycobacterium leprae. Diseases caused by NTM are called nontuberculous mycobacterial diseases (disease caused by NTM). In recent years, as the detection rate has gradually increased, the corresponding understanding of the various diseases caused by it has also gradually increased. Most of the nontuberculous mycobacteria are saprophytic bacteria with low virulence and are conditionally pathogenic bacteria. The symptoms of nontuberculous mycobacterial disease can be divided into intrapulmonary and extrapulmonary. Extrapulmonary infection can involve the skin, bones, lymph nodes, etc.