Learn about NTM Lung Disease

Key Facts

• Nontuberculous mycobacteria (NTM) are bacteria commonly found in soil and water.
• Everyone comes into contact with NTM, but some people are at greater risk of developing NTM lung disease when exposed to the bacteria.
• Some common symptoms of NTM lung disease are chronic cough, fatigue, weight loss, low fever and night sweats.
• Treatment of NTM lung disease typically requires taking multiple antibiotics, over an extended period of time.

What Causes NTM Lung Disease?

Nontuberculous mycobacteria are a group of bacteria naturally found in soil, water and dust. Everyone inhales NTM into their lungs as part of daily life, and in most people the bacteria do no harm. But a small number of individuals are more likely to get sick when exposed.

NTM belong to a larger family of bacteria called mycobacteria. The most well known are Mycobacterium tuberculosis, which causes tuberculosis, and Mycobacterium leprae, which causes leprosy. All other types are grouped as nontuberculous mycobacteria or NTM. Unlike the others, NTM lung disease is not known to be contagious, except in some cases for individuals living with cystic fibrosis.

The most common type of NTM bacteria in the U.S. is Mycobacterium avium complex (MAC). Most cases of NTM lung disease in the U.S. are caused by MAC. Other NTM species that can affect the lungs are M. abscessus and M. kansasii.

Each type of NTM can affect the body differently. The severity of disease, how it is treated and how you respond to treatment can vary widely from person to person. Factors that may impact the course of your NTM lung disease are the type of bacteria, level of exposure and your overall health.

How NTM Lung Disease Affects Your Body

Most people who are exposed to NTM never get sick. The bacteria gets cleared from the lungs by the body’s natural defense system before an infection develops. However, in some people, especially those with a weakened immune system or an underlying lung disease such as COPD or bronchiectasis, the NTM bacteria is able to invade the lungs and cause an infection. The infection can cause inflammation and lung damage that worsens over time.

There are two main forms of NTM lung disease. The less progressive form is sometimes called nodular bronchiectasis. In this form, the infection causes inflammation of the airways, which over time can cause the airways to become damaged and scarred. As the airways become damaged, they are less able to clear mucus normally, increasing the risk of repeated lung infections like bronchitis and pneumonia. This form of NTM lung disease is most commonly seen in older women of Caucasian or Asian descent without a history of lung disease.

The more severe form of NTM lung disease is called cavitary NTM lung disease. In this type, infection can cause scarring, fibrosis and the formation of cavities or pits in the lung tissue. This damage can lead to respiratory failure. Cavitary disease is more commonly found in people with a smoking history who also have existing lung diseases such as COPD or bronchiectasis.

While most NTM affect the lungs, some types of NTM bacteria can cause disease in other parts of the body, including the lymph nodes, skin, soft tissue and bones.

Who Is at Risk for NTM Lung Disease?

Although anyone can get NTM lung disease, some groups of people are at higher risk . You may be at higher risk if you:

• Have an ongoing lung disease such as bronchiectasis, COPD, cystic fibrosis, silicosis or a previous tuberculosis infection
• Have a weakened immune system, (from cancer, HIV or another autoimmune disorder or due to immune suppressing medication)
• Are over 65 years old
• Are a female

Certain environments and activities can increase exposure to NTM bacteria. Because the bacteria are found naturally in the soil, any activity that stirs up dirt and dust increase the likelihood of breathing in the bacteria. NTM also grows in water and is commonly found in municipal water supplies and household plumbing. It is resistant to disinfectants such as chlorine and can survive at temperatures normally used in home hot water heaters. Showers, hot tubs and other steamy places are potential sources of NTM exposure.