Nontuberculous mycobacteria

This chapter focuses on nontuberculous mycobacteria (NTM), organisms that are ubiquitous in the environment and are thus referred as “environmental mycobacteria” by some experts. <italic>Mycobacterium avium</italic> complex (MAC), which includes <italic>M. kansasii, M. fortuitum</italic>, and <italic>M. abscessus</italic>, is the most common NTM associated with human disease in the United States. It also Although NTM species rarely cause clinically relevant human disease, they are frequently isolated as specimen contaminants. The chapter describes infection that is thought to occur from environmental exposure to the NTM through three potential portals of entry: the respiratory tract, the gastrointestinal tract, and direct inoculation of the skin and soft tissues, although chronic pulmonary disease is the most common clinical manifestation of NTM infection in the immunocompetent host. The chapter discusses the testing, evaluation, and treatment of patients infected by NTM and MAC.