CLS04 - Nocardia, Streptomyces, Rodococcus, and Similar Organisms

  1. Actinomycetes general characteristics - gram stain, ____robic, colony morph, habitat, transmission
    • gram: elongated, gram +, form¬†branching filamentous forms¬†(look like fungi)
    • __robic: aerobic, facultatively anaerobic, or obligately anaerobic
    • morph: dry or mucoid colonies that are sometimes wrinkled
    • may adhere to agar
    • habitat: usually found in soil (aerobic)
    • worldwide dstr, but prevalent in humid areas
    • transmission: penetrating wounds, abrasions
    • inhalation MAY transmit thermophilic actinomycetes
  2. (brief) what are the two primary nocardia's and what disease do they cause?
    • N. asteroides: majority of pulmonary/internal infections
    • N. basiliensis: majority of skin infections
    • mycetoma - chronic, localized, painless, subcutaneous
    • lymphocutaneous infections
    • skin abscesses
  3. Nocardia asteroides - virulence factors, diseases
    • Facultative intracellular pathogen in various cells
    • Virulence factors: resistance to intracellular killing
    • tropism for neuronal tissue (EEK)
    • inhibit phogosome-lysosome fusion
    • produces large amt catalse and hemolysins (much damage)
    • diseases: chronic pulmonary infections
    • lung lesion -> pneumonitis -> necrosis -> spread -> dissemination to brain, other organs
  4. Nocardia basiliensis - diseases
    • Cutaneous infections
    • Nocardiosis
    • Hands/feet mostly (rarely lungs/brain)
    • innoculation from sliver/thorn
    • subcutaneous abcess destroys tissues and bone (actinomycotic mycetomas)
    • swelling, draining sinuses, sulfur granules
    • *NOTE - organs teaming with sulfur granules ("popcorn")
  5. Cultivation of Nocardia
    • Slow growing on std media (normal flora may overtake)
    • Special media: solid medium using paraffin (for isolation)
    • Buffered charcoal-yeast etract medium
    • martin lewis
    • CNA (for optimal recovery)
    • Sabourad dextrose agar
    • *NOTE - Actinomycetes OTHER THAN Nocardia should be plated to routine and selective media and incubated for 2-3wks
  6. Nocardia and acid-fastness?
    • Nocardia considered PARTIALLY acid fast
    • Unusual long-chain fatty acids in their cell walls
    • retain carbolfuchsin dye during mild acid decolorization (show reddish-to-purple filaments)
  7. Brief disease information about non-Nocardia Actinomycetes (Rhodococcus, Streptomyces, Gordonia, Tsukamurella, Tropheryma whipplei)
    • Rhodococcus: catheter-related
    • pulmonary infections, bacteremia, skin/wound infections
    • Streptomyces: smelly
    • Actinomycotic mycetoma
    • Gordonia: usually a tag-along
    • rarely skin infections, cathere-associated sepsis
    • Tsukamurella: MOST SMELLY
    • peritonitis, abscess, cutaneous lesions
    • Tropheryma whipplei: often fatal
    • Whipple disease
    • diarrhea, weight loss, mal absorption, artharlgia, abdominal pain
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CLS04 - Nocardia, Streptomyces, Rodococcus, and Similar Organisms
CLS04 - Nocardia, Streptomyces, Rodococcus, and Similar Organisms