Nontuberculous mycobacteria (NTM), also known as environmental mycobacteria, atypical mycobacteria and mycobacteria other than tuberculosis (MOTT), are mycobacteria which do not cause tuberculosis or leprosy (also known as Hansens disease). NTM do cause pulmonary diseases that resemble tuberculosis. Mycobacteriosis is any of these illnesses, usually meant to exclude tuberculosis. They occur in many animals, including humans and are commonly found in soil and water. Introduction
Mycobacteria are a family of small, rod-shaped bacilli that can be classified into three main groups for the purpose of diagnosis and treatment:

Mycobacterium tuberculosis complex, which can cause tuberculosis: M. tuberculosis, M. bovis, M. africanum, M. microti and M. canetti
M. leprae and M. lepromatosis,  which cause Hansens disease, also called leprosy
Nontuberculous mycobacteria (NTM) are all the other mycobacteria that can cause pulmonary disease resembling tuberculosis, lymphadenitis, skin disease, or disseminated disease. Although over 150 different species of NTM have been described, pulmonary infections are most commonly due to Mycobacterium avium complex (MAC), Mycobacterium kansasii, and Mycobacterium abscessus (see image). Taxonomy
In 1959, botanist Ernest Runyon put these human disease-associated bacteria into four groups (Runyon classification):
Photochromogens develop pigments in or after being exposed to light. Examples include M. kansasii, M. simiae, and M. marinum. Scotochromogens become pigmented in darkness. Examples include M. scrofulaceum and M. szulgai. Nonchromogens include a group of prevalent opportunistic pathogens called M. avium complex (MAC). Other examples are M. ulcerans, M. xenopi, M. malmoense, M. terrae, M. haemophilum, and M. genavense.
The most common species were M. marinum, accounting for 45% of cases and M. chelonae and M. abscessus, together accounting for 32% of patients. M. chelonae infection outbreaks, as a consequence of tattooing with infected ink, have been reported in the United Kingdom and the United States.Rapidly growing NTMs are implicated in catheter infections, post-LASIK, skin and soft tissue (especially post-cosmetic surgery) and pulmonary infections. Pathogenesis
The most common clinical manifestation of NTM disease is lung disease, but lymphatic, skin/soft tissue, and disseminated diseases are also important.Pulmonary disease caused by NTM is most often seen in postmenopausal women and patients with underlying lung disease such as cystic fibrosis, bronchiectasis, and prior tuberculosis. It is not uncommon for alpha 1-antitrypsin deficiency, Marfan syndrome, and primary ciliary dyskinesia patients to have pulmonary NTM colonization and/or infection. Pulmonary NTM can also be found in individuals with AIDS and malignant disease. It can be caused by many NTM species, which depends on region, but most frequently MAC and M. kansasii.Clinical symptoms vary in scope and intensity, but commonly include chronic cough, often with purulent sputum. Hemoptysis may also be present. Systemic symptoms include malaise, fatigue, and weight loss in advanced disease. The diagnosis of M. abscessus pulmonary infection requires the presence of symptoms, radiologic abnormalities, and microbiologic cultures. Lymphadenitis can be caused by various species that differ from one place to another, but again, MAC is the main cause worldwide. Most patients are aged less than 5 years, but the incidence is rare for children having BCG vaccine.