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Predominant Fungal Sterol
Ergosterol
Fungi Staining
- Unstained w/ Gram except Candida
- use Calcofluor, silver stains, Periodic Acid-Schiff (PAS)
Fungal Cell Wall (3)
- Mannan - mannose polymer. fungal cell coat matrix.
- Glucan - glucosyl polymers.
- Chitin (not in all fungi)
Types of Fungi
- Yeast
- Molds
- Dimorphic Fungi
Anti-Fungals
- Amphotericin (ergosterol binding)
- Azoles - (p450 = > methysterol but < ergosterol)
- Echinocandins (1,3-B-D-Glucan synthesis inhibitor)
- Flucytosine (tymidylate synthetase - DNA synthesis inhibitor)
Amphotericin
- Ergosterol binding protein, "punch holes in wall"
- Almost all fungi
- Nephrotoxcitity
Azoles
- Methysterol > Ergosterol.
- binds Cyp450
- Imidazoles - topical
- Triazoles - oral + IV (serious infections)
- Fluconazole + Voriconazole (Candida)
- Itraconazole, Voriconazole, Posaconazole - candida + mold
- Liver toxicity
Echinocandins
- 1,3-B-D-Glucan Synthesis Inhibbitor
- Candida + Asperigillus (Serious Infections)
- Not Cryptococcus + Zygomycetes (1,6-B-D-Glucan)
- Well tolerated w/ headache + liver enzyme elevation
- kidney toxicity
Flucytosine
- DNA Synthesis : thymidylate synthetase
- combination w/ amphotericine for cryptococcal meningitis (Monotherapy = resistance)
Candida
- albicans, glabrata (hospital, takeover albicans)
- yeast
- mouth, vagina, GI
- antibiotics, immunodeficiency (chemo or anti-metabolites), GI surgery (spillage)
- thrush, diaper rash
Cryptococcus
- encapsulated yeast, budding
- bird droppings
- neoformans + gattii
- polysacc + melanin (protection)
- 37oC growth
- immunocomprimised -> meningitis (sub-acute/chronic)
- India Ink, antigens, grown on media
- Ampho -> Fluconazole
Aspergillus
- mold
- immunocompromised (transplant)
- fumigatus (most sig.), niger (otitis externa)
Broad Manifestations
- Lung manifestations (ABPA - chronic allergy, Aspergilloma - fungus ball from TB cavity)
Invasive
- Lung -> BVs
- look for hyphae or galactomannan antigen
- NOT fluconazole
Zygomycete
- mold aka mucormycosis
- pathogens:  rhizopus, rhizomucor, cunninghamella
- rhinocerebral disease (nose + brain)
- HIGH mortality
Sporotrichosis
- dimorphic fungus
- cutaneous disease
- rose gardeners (soil or infected plants)
- string of red, nodular lesions.
Histoplasma Capsulatum
- Ohio and Mississippi (also Blasomyces Dermatitidis)
- Histoplasmosis (Caves + bird droppings)
- Acute = asymptomatic / flu-like
- chronic - mediastinal granuloma + fibrosis, pulmonary, disseminated
Coccidioides Immitis
- "Valley fever"
- Southwest US
Blastomyces Dermatitidis
- Ohio + Mississippi
Pneumocystis Jiroveci
- PCP (PneumoCystis Pneumonia)
- Lack Ergosterol
- prevented w/ trimethoprim + sulfamethoxazole to immunodeficient patients.
Dermatophytes
- Animals, Soil, Humans
- Ring worm, athlete's foot, jock itch.
- scrapings of skin examined microscopically.
- topical + oral therapy.
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