Figure 1.

Illustrates our proposed virulence-exposure-host model for NTM disease. Virulence: High virulence NTM carries virulence antigens, although those antigens are largely unknown. Susceptible patient is defined as a person with chest wall abnormality, anatomical lung abnormalities, such as bronchiectasis, COPD, and asthma, and minor immune system abnormalities such as Mendelian susceptibility to mycobacterial disease. Infection: infection is defined as epithelial colonization by NTM without any evidence of tissue invasion including clinical and radiological evidence. Immunosuppressed patient is defined as a person with active malignancy except skin basal cell carcinoma on chemotherapy medication(s) and radiotherapy and HIV/AIDS, significant primary immunodeficiency, and corticosteroids therapy.