Nontuberculous Mycobacterial Lung Disease (NTM-LD)

Who is at Higher Risk?

Anyone can get NTM-LD. It can be seen both in people without pre-existing lung disease, as well as those whose lungs have been damaged by other conditions, such as

• Bronchiectasis
• COPD
• Asthma
• Lung cancer
• Cystic fibrosis
• Alpha-1 antitrypsin deficiency

A weakened immune system (due to medications or other illnesses)³

Note: Some people with healthy lungs and no known risk factors can still develop NTM lung disease. Researchers are still working to understand why this happens.

Types of NTM

Although scientists have found nearly 200 NTM species that can cause NTM-LD, most NTM-LD in the United States is caused by mycobacterium avium complex (MAC) and, to a lesser extent, M. abscessus. They are often described by how fast they grow in the lab:⁴

• Slow Growers: These take longer to show up in lab tests. The most common type is MAC. Others include M. kansasii and M. xenopi.
• Rapid Growers: These grow more quickly in the lab. Common types include M. abscessus, M. chelonae, and M. fortuitum.

Note: Mycobacterial culture final results can take up to 6 to 8 weeks.

How NTM Lung Disease is Diagnosed

Diagnosing NTM-LD can be difficult because the organisms are found naturally in the environment. Health care professionals generally seek evidence that organisms are causing disease, rather than just present (i.e., a colonizer that does not require further evaluation or treatment). Diagnosis involves:

• Medical history: A review of your symptoms and past health issues.
• Imaging: High-resolution CT scan of your chest to look for specific patterns of lung damage.
• Sputum cultures: You may be asked to provide several sputum (mucus) samples. These are tested with an acidfast‑ bacilli (AFB) smear and culture.
  • The AFB smear is a rapid test that can suggest active infection within 1–2 days. A positive test can suggest greater suspicion of a true infection.
  • Because NTM grow slowly, the culture results can take up to 6–8 weeks.⁶
• Bronchoscopy (as needed): If a sputum sample is unable to be provided or if your sputum tests do not show NTM, but it is suspected, a bronchoscopy may be recommended.⁶

Note: Guidelines require at least two separate positive sputum samples to confirm if a person has NTM-LD.⁶

• Antibiotics: NTM-LD usually requires a combination of 3 to 4 antibiotics at the same time. Treatment may last around 18–24 months. Therapy generally continues for 12 months after getting negative sputum test results.³ These medicines can be taken as pills, nebulized antibiotics, or given through an IV (a tube inserted into a vein).
• Airway clearance: Mucus can build up in the airways and become thick and sticky. This excess mucus can block the airways, lead to frequent coughing, and make it difficult to clear the lungs. If you have bronchiectasis, the airways can change shape, leading to even more mucus buildup. Airway clearing techniques help break up mucus, making it easier to clear. This can lessen shortness of breath, reduce coughing, and improve oxygen levels.⁷
• Nutrition: Fighting lung infection requires great nutritional status. Many people with NTM-LD have a poor appetite; this can worsen weight loss and nutritional status.⁸ Talking to a registered dietitian or nutritionist can give you valuable insights to help meet nutritional needs.
• Pulmonary rehabilitation and exercise: Pulmonary rehabilitation is a supervised program designed to improve fitness and strength with an exercise plan tailored to you. It can help you better manage low energy and shortness of breath, common in NTM-LD. The program also teaches breathing techniques, energy-saving tips, and provides education about your condition.⁸
• Surgery: Surgery may be considered if the infection is severe, localized to just one area of the lung, and is not responding well to antibiotics.⁸

Ways to Reduce Exposure

Because NTM is found in water and soil, it cannot be avoided completely. However, you can lower the risk of inhaling or ingesting the organisms:

• Avoid steam and mist: Stay away from hot tubs, spas, and indoor swimming pools where steam can carry the NTM organisms.
• Turn up the heat: Set your water heater to more than 130°F (55°C) to help kill the organisms.
• Choose safer showering: Consider taking baths instead of showers when possible. Use a large-droplet showerhead, consider soaking it regularly in bleach to reduce bacteria, and run the exhaust fan to minimize steam inhalation.¹¹
• Outdoor safety: Consider wearing a mask and wetting the soil while gardening to avoid breathing in dust and dirt.⁷

Note: While these steps are often recommended and may reduce exposure, there is limited clinical evidence that they ultimately reduce infection (or reinfection) risk.

Is NTM Contagious?

Unlike tuberculosis (mycobacterium tuberculosis), NTM-LD is generally not contagious and does not spread from person to person. However, in rare cases, specific types of NTM can spread between people who have cystic fibrosis.⁹

What to Expect with NTM-PD

If you have been diagnosed with NTM-LD, it’s important to seek care from an experienced pulmonologist or infectious disease specialist. Many people find that symptoms get better after starting medication, but NTM-LD can be difficult to completely cure. Treatment is often prolonged, sometimes lasting years.

The infection is considered adequately treated only when sputum culture samples remain free of NTM for at least 12 consecutive months.⁷ Even after successful treatment, there is a 40–50% risk of reinfection with the same or a different strain, so ongoing monitoring and lung care remain important.¹⁰

To help navigate NTM-LD with your care team, download the NTM Lung Disease Management Tool and other resources to guide conversations about diagnosis, symptom management, and treatment.