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Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are found in many different types of environments. Although most of us are naturally exposed to these organisms and aren’t harmed by them, a small group of people — usually those who have weakened immune systems or underlying lung disease — are at risk of developing an infection from NTM.

One of the most common NTMs that causes lung disease is Mycobacterium avium-intracellulare complex, which often is referred to as MAC or MAI. However, there are several types of NTMs that can cause infections. NTMs most commonly cause infection in the lungs, and more than 86,000 people are living with NTM lung disease in the U.S. These organisms can also cause infections at other sites, such as the skin, bone and joints; however, these tend to be less common.

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What Are NTM Infections?

Nontuberculous mycobacteria (NTM) infections are illnesses caused by a subset of bacteria called mycobacterium. NTM includes all mycobacterium species except for those that cause tuberculosis and leprosy.

NTM infections can involve many parts of your body, including the:

  • Lungs (most common).
  • Skin.
  • Bones or joints.
  • Lymph nodes.
  • Blood.
  • Any part of your body where you have a medical device. This includes a feeding tube, breathing tube, pacemaker, or catheter inserted into your veins or arteries.

NTM infections are rare and most often affect people with lung disease or weak immune systems.

Medication can cure these infections, but the bacteria are resistant to antibiotics. Treatment often includes multiple medicines taken for several weeks or months.

What causes NTM infections?

There are more than 180 naturally occurring mycobacterium strains in the environment that can cause NTM infections. They live in soil, dust, plants, natural water sources (such as lakes and rivers), and tap-treated drinking water we use to shower, cook, and drink. You can inhale the bacteria through the air or ingest it through water.

People come into contact with these bacteria every day. Most of the time, they don't make you sick. But sometimes, — especially if you have chronic lung disease or a weak immune system due to another illness or disease — these bacteria can infect you.

In rare cases, you can also get an NTM infection in the hospital through contaminated surgical tools or when you are being treated for a wound that hasn't healed yet.

What are NTM risk factors and complications?

NTM risk factors

You are most at risk for an NTM infection if you:

  • Have a breathing tube, feeding tube, central venous line, or other medical device that goes into your body.
  • Have a chronic lung condition such as bronchiectasis or cystic fibrosis.
  • Have conditions that can weaken your immune system, such as HIV or cancer.
  • Inject drugs intravenously.
  • Take immunosuppressive medications.

Complications of NTM infections

Some NTM infections can become severe and cause symptoms for months or even years. They are usually not fatal.

NTMs can cause lung scarring and cavities (abnormal, air-filled spaces within the lung).

If you have a serious medical condition or a severe NTM infection, it could lead to more serious health problems. People with lung disease or diseases that affect the lungs are most at risk for complications like lung failure.

What Are the Signs and Symptoms of NTM Infections?

When NTM infections involve the lungs, some of the common symptoms are:

  • Persistent cough.
  • Coughing up blood.
  • Excess mucus or phlegm.
  • Fevers.
  • Night sweats.
  • Shortness of breath.
  • Weight loss.

NTMs in other areas will typically cause symptoms at the site of the infection. This could include a nonhealing wound or an infection that doesn’t respond to typical antibiotics.

When should I see a doctor about my nontuberculous mycobacteria symptoms?

It can be hard to tell if you have an NTM infection because the symptoms are similar to infections of other more common bacteria. If your symptoms don't improve or worsen, see a doctor, especially if you have a medical device, a lung condition, or a weakened immune system.

You may need to see a pulmonologist if you have a lung issue or disease that affects your lungs, or your symptoms involve your lungs.

How Do You Diagnose an NTM Infection?

Since many of the symptoms of NTM infections are common to many other illnesses, your doctor will need to take a detailed medical history and ask about when your symptoms started. They will also need to perform some tests to confirm the cause of the infection. The diagnosis is usually confirmed using a specialized culture.

Your doctor may also consult an infectious disease expert trained in diagnosing and treating rare and troublesome infections.

Tests to diagnose an NTM infection

A doctor will need to perform tests and cultures to determine the type of NTM causing the infection and the best treatment. These tests will vary depending on the location of the infection, your symptoms, other medical issues, and risk.

Possible tests include:

  • A lung culture or biopsy — Doctors may take fluid or material from the lungs to test for infection and bacteria.
  • Wound culture — They may test fluid from your sores or skin.
  • Blood culture — When the infection might be in your bloodstream, your doctor will take blood and send it to a lab to check for NTMs.
  • Imaging tests — Your doctor may request an x-ray or CT scan, which shows them the inside of your lungs so they can look for any cavities or problems in the lungs.

How Do You Treat NTM Infections?

You may not need treatment if you are healthy or the NTM infection is slow-progressing or mild. If this is the case, your doctor may monitor your symptoms to see if the infection goes away on its own.

Most people, especially those with lung or other health conditions, will need to take medication to treat the infection and improve symptoms.

Medication to treat NTM infections

A doctor will prescribe antibiotics for an NTM infection. However, you may need to take several medicines at the same time for a long time.

The type and number of medicines you need will vary depending on the type of NTM infection and how severe it is.

If you have an NTM infection in your lungs or it is affecting your breathing, you may need to take medicines through an inhaler or breathing treatment.

Surgery to treat NTM infections

If you have an NTM infection in the lung or other part of your body, you may need surgery to remove the infected area.

You may also need to take medication after the surgery.

How long does it take to recover from an NTM?

NTM infections are difficult to cure and take a while to go away. You may need to be on more than one medicine for many months.