Micro: Fungal and Parasites Flashcards
Name the 4 dimorph fungi.
Can Have Both Shapes
- Coccidiodes
- Histoplasma
- Blastomyces
- Sporothrix
How are the dimorphs differentiated from one another?
unique characteristics of yeast form.
respiratory symptoms are very similar between all dimorphs
Geography of Coccidiodes immitis.
Desert Southwest of U.S.
Characteristic yeast form of C. immitis.
Spherule
What lab test differentiates fungi and parasites from other microbes?
KOH prep
Treatments and MOA for fungal infections.
Azoles (Fluconazole) is primary medication
-prevents synthesis of ergosterol
Amphotercin B: used in severe acute cases and pregnant patients because azoles are Teratogenic
-targets ergosterol creating a pore in the cell wall of fungal cells
Characteric yeast form of Blastomyces dermatitidis.
Broad Based Budding yeast
Pathogenesis of Histoplasma capsulatum.
Intracellular yeast: infects macrophages and plasma cells
Source of Histoplasma.
Bird and bat dung
-spelunking in caves
“Pilot’s Wheel” budding yeast.
Paracoccidiodomycosis
Paracoccidiodes brasiliensis
Acute Angle budding hyphae in yeast
Aspergillus sp.
Presentation of a patient with Farmer’s Lung and Tx.
Dry cough and chest tightness that occurs over and over again. Symptoms regress when taken away from offending agent. Alergic Aspergillosis sp. is a common cause.
Tx: for any Allergic Aspergillosis use oral corticosteroids
Pathogenesis and Tx for Non-invasive Aspergillosis.
Fungus grows in a cavity in the lungs (fungal ball or aspergilloma). Only occurs after some other disease has occurred: TB, CF, chronic bronchitis.
Tx: surgical excision
Risk factors for invasive Aspergillosis.
IC patients: transplant, leukemia, lymphoma, AIDS, corticosteroid therapy.
Tx for invasive Aspergillosis
Voriconazole
Disease caused by Zygomycosis sp. and characteristic of yeast for diagnosis.
Mucor
-90 degree branched hyphae
Population most at risk for Mucor and unique clinical presentation.
Ketoacidotic Diabetics
-black pus from eyes, nose, and mouth
Tx for Mucor.
Amphotercin B
1 AIDS associated infection.
Pneumocystis jiroveci
-presents as atypical pneumonia
How does Pneumocystis appear on Giemsa stain microscopy?
Dented Helmets
Only lung parasite we need to know.
Paragonimus westermani (Lung Fluke)
Intermediate host of the lung fluke.
Snail
Presenting respiratory symptoms of lung fluke.
Rust colored sputum (or coffee ground sputum)
-often mistaken for TB
How can a lung fluke be differentiated from TB?
Eggs found in sputum
