• gram⁺ slender rods, acid-fast
• cell wall
  • hydrophobic - strong permeability barrier - resistance
  • porins
  • major Ag component - liberated proteins inc "tuberculin"
• growth
  • aerobic
  • reside and proliferate w/in macrophage
  • resistant to drying and disinfectants, but not heat
  • can grow in vitro at 37º but not room temp
  • require enriched growth media
  • slow growth
  • clumped appearance
• infection - droplet nuclei
• no exotoxins or overt virulence factors
• elecits protective immunity, but pathological hypersensitivity
• clinical picture
  • primary - fever, malaise, Gohn complex
  • reactivation - cough, hemoptysis, fever, fatigues, weight loss, caseating necrosis on radiography
• diagnosis
  • tuberculin test - DTH to PPD
  • laboratory - acid fast bacilli in sputum, culture
• long-term antibiotic combination treatment

• acid fast obligate intracellular bacillus
• tuberculoid form (CMI)
  • CD4⁺ Ts --> IL-2, IFNγ, IL-12 --> promote healing
  • macules
  • few bacilli in lesions
  • non-progressive, usually non-contagious
• lepromatous form
  • CD8⁺ Ts --> IL-4, IL-10 --> suppress healing
  • extensive nodular skin lesions and deformation
  • abundant bacteria in lesions
  • progressive
• Diagnosis
  • acid-fast bacilli in skin scrapings
  • culture? armadillos, mouse foot pads
  • serological test
• Treatment - dapsone + rifampin + clofazimine for lepromatous

• all acid fast, found in soil and environment
• cause granulomatous disease resistant to treatment, especially in immunocompromised
• M. kansasii and M. avium-intracellulare complex - cause TB-like disease
  • MAC causes systemic infection in AIDS patients

• gram⁺ anaerobic, non-acid fast branched bacilli
• commensals, opportunistic pathogens
• sulfur granule
• inflammation of mucosal surfaces (poor dental hygeine)
• treatment - penicillin G

Nocardia asteroides

Nocardia brasiliensis

• gram⁺, aerobic, branched, weakly acid-fast opportunists
• N. asteroides - acute bronchopneumonia with dyspnea, cough
• N. brasiliensis - pustules and lesions with sinuses at injured sites
• Treatment - sulfonamides