Published: 18 Jun 2025

ICD9: 031.0      ICD10: A31.0      ICD11: XN96Q

Nontuberculous Mycobacteria (NTM), also known as atypical mycobacteria, environmental mycobacteria, or mycobacteria other than tuberculosis (MOTT), are a group of mycobacteria species that are different from *Mycobacterium tuberculosis*, the bacteria that causes tuberculosis (TB), and *Mycobacterium leprae*, the bacteria that causes leprosy.


Here's a breakdown of key aspects of NTM:

Diversity: NTM encompass a wide range of species. Over 190 different species have been identified, each with varying levels of pathogenicity and environmental preferences.

Environmental Sources: Unlike TB, which is primarily spread person-to-person, NTM are commonly found in the environment, including:

Water: Tap water, hot tubs, swimming pools, natural bodies of water
Soil: Garden soil, potting mix
Dust

Transmission: People acquire NTM infections by exposure to these environmental sources. This can happen through:

Inhalation: Breathing in contaminated water droplets or dust.
Ingestion: Swallowing contaminated water.
Skin contact: Through wounds or broken skin, especially during activities like gardening or cleaning.

Infections: NTM can cause a variety of infections, most commonly:

Pulmonary disease: Lung infections resembling TB, often affecting people with underlying lung conditions like COPD, cystic fibrosis, or bronchiectasis.
Skin and soft tissue infections: Often occurring after trauma or surgery, particularly in areas exposed to contaminated water.
Disseminated disease: In people with weakened immune systems, NTM can spread throughout the body, affecting multiple organs.
Lymphadenitis: Swollen lymph nodes, primarily in children.

Risk Factors: Certain factors increase the risk of NTM infection:

Pre-existing lung disease: COPD, bronchiectasis, cystic fibrosis
Weakened immune system: HIV/AIDS, organ transplant recipients, people taking immunosuppressant drugs
Age: Older adults are more susceptible to pulmonary NTM, while children are more prone to lymphadenitis.
Structural lung abnormalities: Scoliosis, pectus excavatum

Diagnosis: Diagnosis of NTM infection involves:

Clinical evaluation: Assessing symptoms and risk factors.
Imaging: Chest X-rays or CT scans to evaluate lung involvement.
Culture: Growing NTM from samples (e.g., sputum, skin biopsy, blood) to identify the specific species. Multiple positive cultures are usually required to confirm pulmonary NTM infection.
Excluding TB: Ruling out TB as the cause of the infection.

Treatment: NTM infections can be challenging to treat because:

Antibiotic resistance: Many NTM species are naturally resistant to common antibiotics.
Prolonged therapy: Treatment often requires a combination of multiple antibiotics for a long duration (12-24 months or longer).
Side effects: The antibiotics used to treat NTM can have significant side effects.

Prevention: Preventing NTM infections involves:

Good hygiene: Washing hands thoroughly, especially after exposure to soil or water.
Water safety: Using appropriate disinfectants in hot tubs and swimming pools.
Avoiding exposure: Minimizing exposure to potentially contaminated water or soil if you have risk factors.
Avoiding smoking: Smoking is a risk factor for NTM pulmonary disease

Common NTM Species:

*Mycobacterium avium complex (MAC):* The most common cause of pulmonary NTM disease. Includes *M. avium* and *M. intracellulare*.
*Mycobacterium kansasii:* Another common cause of pulmonary disease.
*Mycobacterium abscessus:* A rapidly growing species that can cause pulmonary, skin, and soft tissue infections. It is often highly resistant to antibiotics.
*Mycobacterium marinum:* Causes skin infections, often acquired from aquariums or swimming pools ("swimming pool granuloma").

Important Considerations:

Colonization vs. Infection: NTM can colonize the lungs or other body sites without causing active infection. Distinguishing between colonization and true infection is important for treatment decisions.
Individualized Treatment: Treatment plans should be tailored to the specific NTM species, the severity of the infection, and the patient's overall health.
Consultation with a Specialist: Managing NTM infections often requires the expertise of a pulmonologist or infectious disease specialist experienced in treating these infections.

In summary, NTM are a diverse group of mycobacteria found in the environment that can cause a variety of infections, particularly in individuals with underlying risk factors. Diagnosis and treatment can be challenging and require specialized expertise.