Nontuberculous Mycobacteria
• NTM are ubiquitous environmental organisms that cause a spectrum of disease primarily involving the lungs (80%), skin and soft tissues, lymph nodes, and disseminated disease. Susceptibility testing and an infectious disease consultation are recommended to guide treatment.
Different species are commonly associated with specific clinical presentations:î Pulmonary infection: Mycobacterium avium complex (isolated in 85% of the cases), Mycobacterium kansasii, and Mycobacterium abscessus are the most common pathogens involved.
î Skin, soft-tissues, and bone infection: Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium scrofulaceum, Mycobacterium marinum (“fish tank granuloma”), and Mycobacterium ulcerans (Buruli ulcer).
î Lymphadenitis: M. avium complex and M. scrofulaceum.
î Disseminated: M. avium, M. kansasii, M. abscessus, M. chelonae, and Mycobacterium haemophilum (see Chapter 16, Sexually Transmitted Infections, Human Immunodeficiency Virus, and Acquired Immunodeficiency Syndrome).41
• Mycobacterium leprae is classified separately from other NTM because of its potential for human-to- human transmission. When rarely encountered in the US, it is associated with exposure to armadillos. Clinically, typical findings include hypopigmented anesthetic skin lesions.