Micro-Fungi!

Histoplasmosis

-Systemic mycoses
-Endemic to Ohio river valley
-Can be asymptomatic, cause pneumonia, or disseminated disease in the IC host.
-From bird or bat droppings
-Intracellular - yeast fills MACs

Blastomycosis

-Mississippi River valley
-Spores in soil and rotten wood
-Causes inflammatory lung disease and can disseminate to skin and bone
-Forms granulomatous nodules
Culture on Sabouraud's agar
-Hardest to get and hardest to have
-Big, Broad-Based Budding

Coccidioidomycosis

-Southwest
-Pneumonia and meningitis
-Can disseminate
-Endospores seen within spherule

Paracoccidioidomycosis
-Where?
-Classic microscopic appearance?

-Rural Latin America
-Captain's wheel appearance of budding yeast.

Systemic Mycoses

-Can mimic TB and have granuloma formation
-Can cause pneumonia and disseminate
-Caused by dimorphic fungi
-Examine with silver stain or grow on Sabouraud's agar or blood agar

Tinea versicolor
-organism that causes it
-Microscopic appearance

-Malassezia furfur
-Spaghetti and meatball on KOH prep

Opportunistic Fungal infections (5)

1. Candida albicans
2. Aspergillus fumigatus
3. Cryptococcus neoformans
4. Mucos/Rhizopus
5. PCP

Aspergillus fumigatus
-diseases
-morphology

-Can cause asthma-type hypersensitivity rxn (IgE mediated) with bronchospasm, increase in IgE Abs and eosinophilia
-Can also cause lung cavity "fungus ball" in TB patients
-Can cause invasive pneumonia and disseminated disease in ICs
-Mold with septate hy

Cryptococcus neoformans

-Heavily encapsulated yeast
-Soil, pigeon poo
-Sabouraud's agar/India ink
-Can cause cryptococcal meningitis cryptococcosis in IC
-CSF shows yeast with surrounding halo

Mucor and Rhizopus
-Disease
-In Who?
-Morphology

-Mucormycosis - think rhinocerebral with frontal lobe abscesses
-In DKA pts or leukemia
-Can also proliferate in BVs and cause infarction/necrosis in distal tissue
-Irregular non-septate hyphae branching at 90 degrees.

Pneumocystis jiroveci

-Causes diffuse interstitial pneumo
-Most infections asymptomatic
-In AIDS pts, starts prophylaxis when CD4 < 200
-Identified by methenamine silver stain of lung tissue
-Treat with TMP-SMX

Sporothrix schenckii

-Causes sporotrichosis
-Rose-gardener's disease
-Causes LOCAL pustule/ulcer with noduels along draining lymphatics
-Cigar-shaped budding yeast in pus
-Tx with itraconazole or KI