Updated: 1/15/2019

Mycobacteria Other Than Tuberculosis (MOTTS)

Review Topic
  • A 36-year-old HIV positive woman, non-compliant with treatment, presents to the clinic with a 1 month history of fever, fatigue, cough, and weight loss. Her temperature is 102.2°F (39°C), blood pressure is 135/90 mmHg, pulse is 100/min, and respirations are 22/min. The patient appears cachectic and markedly pale on physical exam. CD4 count is 39 cells/mm3. Chest radiography demonstrates nodular bronchiectatic changes and an upper lobe fibrocavitary pattern.
  • Definition
    • infectious mycobacterium that is not tuberculosis, which can cause 4 clinical syndromes
      • pulmonary disease
        • caused by Mycobacterium avium complex (MAC) 
      • superficial lymphadenitis
        • caused by 
          • MAC (more common in children)
          • M. scrofulaceum
          • M. malmoense
      • disseminated disease in immunocompromised patients (e.g., AIDS)
        • most commonly caused by MAC
      • skin and soft tissue infection
        • most commonly caused by M. marinum
          • typically due to direct inoculation of the organism
  • Epidemiology
    • incidence
      • the most common nontuberculous species that cause disease in humans in the United States are
        • MAC
        • M. kansasii
Nontuberculous Mycobacterium
Clinical Presentation
Making the Diagnosis
Pulmonary disease
  • Symptoms are typically non-specific and depend on if the patient has underlying pulmonary disease
    • patients with underlying pulmonary disease typically present similar to tuberculosis (e.g., cough, weight loss, upper lobe infiltrates, and cavities)
  • Symptoms include
    • cough (dry or productive)
    • fatigue
    • malaise
    • dyspnea
    • weakness
  • Based on clinical and radiographic findings (e.g., nodular or cavitary opacities or multifocal bronchiectasis)
  • Sputum acid-fast bacilli and culture
  • Lung biopsy with mycobacterial histopathologic features (granulomatous inflammation or acid fact bacillus), if needed
Superficial lymphadenitis
  • Enlarged lymph nodes
    • most commonly the cervicofacial node in children
    • nontender and unilateral
    • enlarges over the course of weeks
  • Culture or polymerase chain reaction (PCR) of the fistula drainage, tissue, or caseous material
  • Most commonly affects children < 5 years of age
Disseminated disease
  • Fever
  • Fatigue
  • Malaise
  • Anorexia
  • Sequelae of organ involvement
    • bone marrow (neutropenia and anemia)
    • hepatosplenomegaly
  • Blood cultures of the Mycobacterium
  • Risk factors include
    • advanced HIV infection
    • hematologic malignancy
    • tumor necrosis alpha inhibitors or other immunosuppressive agents
Skin and soft tissue infection
  • Skin lesion
    • erythematous or bluish papule or nodule at the site of abrasion
      • lymphadenopathy may be present
  • Culture or PCR of the lesion
  • Fisherman or people who work at aquariums are at risk of developing M. marinum infection
  • Medical
    • macrolide, rifamycin, and ethambutol
      • indication
        • initial empiric treatment option for MAC
      • comments
        • in cases of macrolide-resistance, the regimen is changed to rifamycin, ethambutol, clofazimine, and an intravenous aminoglycoside
        • note, the appropriate treatment for M. marinum has not been identified
  • Dissemination of the nontuberculous mycobacterium can occur in severely immunocompromised patients

Please rate topic.

Average 3.1 of 10 Ratings

Thank you for rating! Please vote below and help us build the most advanced adaptive learning platform in medicine

The complexity of this topic is appropriate for?
How important is this topic for board examinations?
How important is this topic for clinical practice?
Topic COMMENTS (3)
Private Note