Cryptococcus neoformans

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Where is it found?
In guano enriched soils

Pigeons are major carriers in the US
How is cryptococcus neoformans transmitted?
Inhalation of infectious agent
-No person to person transmission

1. spores inhaled into lungs
2. spores lodged into alveoli
3. Dissemination into central nervous system leads to positive culture.
How is disease formed from cryptococcus neoformans?
Disease commonly found in immunosuppressed individuals (lymphoma patients, chronic corticosteroid use, transplant patiens, AIDS)

Asymptomatic infection is common (no symptoms)

80% is AIDS patients, 20-30% in healthy people (mostly elderly)
Pulmonary infection by cryptococcus neoformans
Well defined, non-calcified, nodules on Chest X-ray

symptoms includes pneumonia and tissue necrosis
What is the major clinical outcome of cryptococcus neoformans?
Symptomatic or asymptomatic meningitis
Lab diagnosis of cryptococcus neoformans
Lumbar puncture essential to obtain CSF

Plated on SABOURAUD AGAR
-only virulent strains grow at 37 degrees

Capsule expression essential for virulence
-seen in stains

Stained by
-H&E STAIN
-INDIA INK STAIN
--capsule seen as white halo surrounding yeast cell
Treatment of respiratory/ non CNS infections
fluconazole
Treatment of CNS infections
Amphotericin B + flucytosine for 2 weeks

Fluconazole continued until healed (~10 wks)
Treatment of AIDS patients
Hardest group to treat

Liposomal amphotericin B + flucytosine for more than 2 wks

fluconazole for extended period until healed