Fungi Flashcards
What is mycology
study of fungi, infections are mycoses, cell wall: polysaccharides, mannoproteins
Fungal cell wall features
chitin, mannoproteins, beta-glucans, melanin; Cryptococcus neoformans
Antifungal targets
polyenes: interact with ergosterol, disrupt plasma membrane, burst
azoles: inhibit ergosterol synthesis
allylamines: inhibit ergosterol synthesis
echinocandins: inhibit glucan synthesis (cell wall)
Mold vs yeast
Yeast: unicellular yeast - single cell budding, colonies
Mold: multicellular - hyphae, fuzzy
Candida albicans
Yeast, pseudohyphae - when budding isn’t complete
Reservoir: humans, normal flora of colon; colonization of oral cavity, rectum, vagina
Most common cause of invasive fungal infections in immunocompromised
Treat with fluconazole
Candidiasis infections
thrush: white matches, pseudomembrane that can be wiped off leaveing red area, chronically ill and infants
esophagitis: difficulty/painful swallowing, AIDS-defining infection
Cryptocoocal meningitis
neurologic; can be acute or insidious; fever, vomiting, nuchal rigidty, mental status changes/seizures; increased intracranial pressure, herniation, and death
Cryptococcus neoformans/gattii
only yeast to have a capsule, neurotopics;
Resevoir: bird droppings, soil -> inhalation
Avoid cats in contact with birds/droppings; Spreads preferably to the meninges, opportunistic
Treat with Amphotericin B, fluconazole for maintenance
Mold features
single hyphae will grow from a spore;
hyphae: multinucleated, will into branches
Aerial (vertical) growth - spores for dissemination
infection through spores
Aerosis, inhalation
inoculation in wounds/skin break
Aspergillus fumigatus
mold (eukaryote), septate hyphae - will form inside body
Reservoirs: soil, compost - environment, spores (condida) are inhaled
Infections: invasive sinusitis/rhinosinusitis
Dermatophytes
mold, Resevoirs: environment, direct contact: spores, are inoculated on skin, nails, hair, hyphae grow
cutaneous infections, keratinase
Dimorphic fungus
can switch between mold and yeast, change in response to temperature
“Cold” = mold, filamentous
“Warm” = body temp = yeast
Dermatophytosis
pruritis, scaly lesions, hair loss (tinea capitis)
treat with imidazoles and traizoles: inhibit ergosterol biosynthesis
Tavaborole: inhibits fungal protein synthesis
Terbinafine: reduce ergosterol biosynthesis
Coccidioides immitis
dimorphic fungus, mold in environment, yeast in humans
Reservoir: dry dirt, dust, desert
Endemic in Southwest US, Valley Fever
Valley Fever
slow progression, acute pneumonia
fever, cough, pleuritic chest pain, hemoptysis,
