Pulmonary nontuberculous mycobacterial disease prevalence and clinical features: an emerging public health disease.

RATIONALE: Respiratory specimens with nontuberculous mycobacteria (NTM) are increasingly common; however, pulmonary disease prevalence is unknown.
OBJECTIVES: To determine the disease prevalence, clinical features, and risk factors for NTM disease, and to examine the predictive value of the microbiologic criteria of the American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) pulmonary NTM case definition for true NTM disease.
METHODS: We identified all Oregon residents during 2005-2006 with at least one respiratory mycobacterial isolate. From a population-based subset of these patients, we collected clinical and radiologic information and used the ATS/IDSA pulmonary NTM disease criteria to define disease.
MEASUREMENTS AND MAIN RESULTS: In the 2-year time period, 807 Oregonians had one or more respiratory NTM isolates. Four hundred and seven (50%) resided within the Portland metropolitan region, among which 283 (70%) had evaluable clinical records. For those with records, 134 (47%) met ATS/IDSA pulmonary NTM disease criteria for a minimum overall 2-year period prevalence of 8.6/100,000 persons, and 20.4/100,000 in those at least 50 years of age within the Portland region. Case subjects were 66 years of age (median; range, 12-92 yr), frequently female (59%), and most with disease caused by Mycobacterium avium complex (88%). Cavitation (24.5%), bronchiectasis (16%), chronic obstructive pulmonary disease (28%), and immunosuppressive therapy (25.5%) were common. Eighty-six percent of patients meeting the ATS/IDSA microbiologic criteria for disease also met the full ATS/IDSA disease criteria.
CONCLUSIONS: Respiratory NTM isolates frequently represent disease. Pulmonary NTM disease is not uncommon, particularly among elderly females. The ATS/IDSA microbiologic criteria are highly predictive of disease and could be useful for laboratory-based NTM disease surveillance.