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,
Histoplasma Capsulatum
dimorphic fungus, mold in environment like Cap’s shield, yeast in humans
Reservoir: soil, bird, or bat droppings
Airborne - inhalation of spores
Histoplasmosis
Systemic - fever, headahce, fatigue
chest pain, dry cough, myalgia, arthralgia
skin: erythema nodosum/multiforme
