What is nontuberculous mycobacteriosis?

The term nontuberculous mycobacteriosis includes all diseases that are caused by mycobacteria but not by the causative agents of  tuberculosis  or leprosy. Mycobacteria are a genus of bacteria that are widespread in the environment. Many of them are harmless to humans, but there are some species that can cause infectious diseases. These include Mycobacterium tuberculosis and Mycobacterium leprae, which cause tuberculosis and leprosy. On the other hand, there are other mycobacteria that can cause diseases in humans. These are referred to as nontuberculous or atypical mycobacteria. In technical jargon they are often abbreviated as “MOTT – Mycobacteria other than tuberculosis”.

Weakened immune system as a risk factor

Nontuberculous mycobacteria are ubiquitous in the environment. Humans are therefore in almost constant contact with this type of bacteria. However, disease usually occurs only in people whose immune systems are weakened. These include, for example, patients who have one of the following risk factors:

Nontuberculous mycobacteriosis is extremely rare in healthy people.

Nontuberculous mycobacteriosis: environmental source of infection

Transmission of nontuberculous mycobacteria is mostly via the environment. Sources of infection are, for example, bodies of water such as lakes and rivers as well as soil and dust, but also drinking water. In addition, infection can occur through unsanitary use of medical devices such as catheters or ventilators. However, there is no evidence of human-to-human transmission.

Lung most commonly affected

Various organs of the body can be affected by nontuberculous mycobacteriosis. The bacteria often cause a  lung infection that  has a similar course to tuberculosis. Symptoms such as coughing up sputum (sometimes bloody), shortness of breath, fever, weight loss and exhaustion can occur.

Less commonly, non-tuberculous mycobacteriosis occurs on the  skin  . A typical skin disease caused by non-tuberculous mycobacteria is the so-called swimming pool granuloma. It occurs primarily in aquarium keepers or people who work in the fish industry and is manifested by nodular skin lesions on the knees, hands and elbows.

Forms of nontuberculous mycobacteriosis

Other forms of nontuberculous mycobacteriosis can include wound infections,  abscesses ,  and sternum osteomyelitis following open-heart surgery. In children under five years of age, a unilateral, painless swelling of the lymph nodes in the neck area (cervical lymphadenopathy) with a slight fever is often the only symptom of nontuberculous mycobacteriosis.

A generalized infection with non-tuberculous mycobacteria can occur, particularly in AIDS patients. The pathogens attack numerous organs such as the liver, spleen, intestines, lungs and bone marrow. However, the symptoms are often non-specific: fever, night sweats, weight loss,  diarrhea  and abdominal pain can indicate many diseases.

Diagnostics very complex

Since non-tuberculous mycobacteria are found practically everywhere and can also be found on the mucous membranes of healthy people, diagnosis is often quite difficult. Depending on the symptoms, samples of sputum, blood, urine, stool, tissue or lymph nodes are taken and examined for the pathogen. As a rule, however, at least three samples must be examined in order to exclude contamination – for example by mycobacteria in tap water. In addition, if a lung infection is suspected, an X-ray or CT image is required to confirm the diagnosis.

Therapy is not always necessary

Non-tuberculous mycobacteriosis is usually treated with a combination of different  antibiotics . However, since the bacteria are resistant to many of the usual antibiotics, aggressive active ingredients often have to be used, which have the associated side effects. In addition, the duration of therapy is up to 24 months. Therefore, once nontuberculous mycobacteriosis has been diagnosed, careful consideration is given to whether the benefits of treatment outweigh the risks.

Criteria for deciding for or against a therapy include the severity of the symptoms, the number of germs in the sample and the findings of the X-ray or CT image. The general condition of the patient must also be taken into account.

Non-tuberculous mycobacteriosis: treatment with antibiotics

If therapy is to be carried out, a combination of three to four of the following antibiotics is usually used:

  • Drugs against tuberculosis such as rifamycin, ethambutol, streptomycin or isoniazid
  • Clarithromycin oder Azithromycin
  • CiprofloxacinMoxifloxacin oder Levofloxacin
  • Prothionamide, Amikacin or Linezolid
  • Tetracycline or Imipenem
  • Sulfonamide oder Trimethoprim und Sulfamethoxazol
  • Tigecyclin

OP sometimes makes sense

When nontuberculous mycobacteriosis is localized—for example, when only one lymph node or a small portion of the lung is affected—surgery to remove the affected area may be a viable treatment option. Surgery combined with antibiotic therapy can also be successful in the case of deeper wound or skin infections.


Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *