Nontuberculous mycobacteria

• Characteristics
  • Acid-fast bacilli: Ziehl-Neelsen stain
• Diseases
  • M. avium-intracellulare (Mycobacterium avium complex infection)
    • Clinical features
      • MAC infection often manifests as disseminated disease and typically occurs in patients with advanced immunosuppression (CD4 counts &lt 50).
      • Night sweats, fever, weight loss
      • Focal lymphadenitis
      • Abdominal pains, diarrhea
      • Widespread involvement of the reticuloendothelial system often causes anemia, hepatosplenomegaly, and/or elevated alkaline phosphatase and lactate dehydrogenase.
    • Histologic findings in the bone marrow include foamy macrophages with intracellular, acid-fast bacilli.
  • M. marinum
    • Fish tank granuloma: skin infection usually of the hand that occur in individuals handling fish (e.g., aquarium handlers)
  • M. scrofulaceum
    • Cervical lymphadenitis in children