Module 11: Lecture 16 Flashcards
Systemic (endemic) pathogens that cause mycoses
-Healthy individual
- Coccidioides immitis
- Histoplasma capsulatum
- Blastomyces dermatidis
Opportunistic pathogens that cause mycoses
-Patient MUST BE IMMUNOCOMPROMISED
- Cryptococcus spp.
- Aspergillus spp.
- Pneumocystis jiroveci
- Exist as mold in nature and yeast in body
- causes valley fever
- soil borne fungus
- non-budding spherule
- release endospores
- Not contagious
- Primary = self-limited
- Disseminated = agressive
Coccidioides immitis
- Tender red nodule rash (delayed allergic response)
- Indicative of a prior coccidiomycosis infection (doesn’t mean you still have it)
- Indicator of good prognosis (CMI is functional)
Erythema nodosum
To identify this organism you would look for spherules in PAS staining or on blood agar at 37 degrees (Saboraud agar 25 degrees- mold)
-Arthroconidia is highly infectious!
Coccidioides immitis
Is there a vaccine for Coccidioides immitis (valley fever)?
No
- Soil based fungus
- Contaminated with bird or bat dropping
- Ohio or Mississippi Valley
- Inside Phagocyte
- Test relies on Antibodies, not Antigen
Histoplasma capsulatum
This fungus resides in moist soil and decomposing organic matter (wood and leaves)
- Farmers, Campers, Hunters, Forrest workers at risk
- Inhalation of spores (condia)
- Remains Extracellular
- “Broad Based Buds”
- Granuloma in lungs (mistaken for cancer)
Blastomycosis
Most likely pathogen on Cryptococcosis?
Cryptococcocus neoformans
- Only fungus with a capsule
- Gram -
- Encapsulated yeast (India ink)
- Diphenol oxidase (Laccase) -Bird seed agar
- Forms brown spot (melanin) from phenol
- Grows at high temps 37-45
- Co-infection with Candida albicans
- Not contagious
- Yeast likes CSF
- Treated with Fluconazole (passes blood brain barrier)
Cryptococcocus neoformans
Growth on Canavanine glycine bromothymol blue (CGB) medium.
If stains blue =
If stains yellow =
Cryptococcocus neoformans = yellow
C.gatti = blue
- Most common refrigerator mold (A. fumigatus = most common)
- Powdery mold
- Usually asymptomatic if immunocompetent
- Surface adhesins (Sialic acid- binding)
- Catalase = oxidative stress
- Some produce Aflatoxin
Asperigillus
If you have Allergic Aspergillosis treat as?
true allergy (steroid)
If you have Aspergillioma and Extrapulmonary it has to be?
Surgically removed then Nystatin
Asperigillus grow atleast ______ cultures?
2
