Evaluation and management of patients with pulmonary nontuberculous mycobacterial infections.

Nontuberculous mycobacteria (NTM) are emerging pathogens increasingly associated with chronic pulmonary disease. NTM are environmental saprophytes found in soil, dust and water and, unlike Mycobacterium tuberculosis, NTM are not transmitted from person to person. Pulmonary disease caused by NTM is a particular problem in older people without underlying immune compromise. The diagnosis of NTM pulmonary disease usually requires either multiple respiratory cultures that grow NTM or heavy growth of NTM from a single bronchoscopy or lung-biopsy specimen. High resolution computed tomography is the most useful radiographic study for diagnosis and to determine the extent of disease. Treatment includes multiple medications with activity against the particular NTM species, as single-drug therapy is likely to select for resistant organisms. Data demonstrating the effectiveness of specific drug regimens for NTM pulmonary disease are limited. Clarithromycin and azithromycin form the backbone of most treatment regimens because these drugs are active against many NTM species. Drug tolerability and cost are the major barriers to successful treatment of NTM pulmonary disease. Adjunctive therapies, including mucus clearance techniques and appetite stimulants, are unproven but may be of value in management of NTM pulmonary disease. Multicenter, randomized trials of macrolide-based therapies are sorely needed to determine the safest and most effective treatments for NTM pulmonary disease.