NTM.

What it is

NTM are a family of bacteria distantly related to the tuberculosis germ but not contagious person-to-person. They live in soil and water, including municipal water systems, shower heads, hot tubs, and decorative fountains. Mycobacterium avium complex (MAC) is the most common species in the United States. The disease is increasing in frequency, especially in women over 50 with slender body type and minor structural lung abnormalities, a clinical pattern sometimes called “Lady Windermere syndrome.”

How it shows up

NTM is slow-moving. Patients often have symptoms for years before diagnosis: chronic cough (often dry, sometimes productive), fatigue, low-grade fevers, weight loss, and gradual decline in exercise capacity. Many patients are initially diagnosed with bronchiectasis, COPD, or chronic bronchitis before the NTM is identified.

How we diagnose it

Diagnosis requires three things: clinical signs (compatible symptoms), radiologic findings (CT showing nodular bronchiectasis or cavitary disease), and microbiologic confirmation (two or more positive sputum cultures for NTM, or one positive culture from a bronchoscopic sample). The microbiologic criteria are strict because NTM can be a colonizer (present without causing disease), over-treatment is a real risk. We also identify the specific species: MAC, Mycobacterium abscessus, and Mycobacterium kansasii are the most common.

How we treat it

Treatment is long and difficult. The standard MAC regimen is a three-drug combination of azithromycin (or clarithromycin), ethambutol, and rifampin, taken for at least 12 months after sputum culture conversion, usually 18–24 months total. Mycobacterium abscessus is more resistant and often requires IV antibiotics for parts of the course. Side effects are common. Many patients also need airway clearance therapy because the underlying bronchiectasis perpetuates the infection. Newer therapies, inhaled liposomal amikacin (Arikayce), improve outcomes in refractory disease. Not every patient with NTM needs treatment.

What you can do

• —Take every dose of every drug, every day, for the full duration. NTM is forgiving of nothing.
• —Do airway clearance daily if you have bronchiectasis.
• —Manage water exposure where possible, let showers run before entering, avoid hot tubs, drain decorative fountains.
• —Get GI side effects managed, not ignored. They’re the most common reason patients stop therapy prematurely.