Nontuberculous mycobacteria

The nontuberculous mycobacteria (NTM) are ubiquitous in the environment; so much so that some experts feel they should be referred to as “environmental mycobacteria.” While there are almost 150 identified NTM species, the most common NTM associated with human disease in the United States are Mycobacterium avium complex (MAC), Mycobacterium kansasii, Mycobacterium fortuitum and Mycobacterium abscessus. Many other NTM species can cause human disease but are generally rarely encountered clinically, while a few NTM species, most notably Mycobacterium gordonae, are frequently isolated as specimen contaminants and almost never cause disease.