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FungalPathogens
lecture 33 greenberg
Question | Answer |
---|---|
most important piece of hx for dx of fungal infections | pt's exposure to specific habitats |
fungal cell walls | beta-1,3-glucans and chitin NOT PG like bacteria |
all capsules are antiphagocytic, virulence factor | Cryptococcus neoformans |
echinocandin target | beta-1,3-glucan, inhibit glucan synthesis |
primary sterol in fungal cell walls | ergosterol, synthesis of it is interrupted by amphotericin B and azoles |
dimorphic pathogens | alternate btwn yeast (in mammalian hosts) and mold forms (in soil), CAUSE OF ENDEMIC MYCOSES |
pseudohyphae | typical of Candida, blastoconidia of yeast continue to grow into elongated sausage-like filaments |
arthrospores | arthroconidia, conversion of preexisting entire hyphal element into smaller conidia that break loose and disseminate to cause dz (Cryptococcus) |
macroconidia/microconidia | small and large conidial forms, typical of tineal infections |
sporotrichosis | from rose thorn prick, gardener |
characteristic endemic mycoses are typical of specific geographic regions | |
histoplasmosis geographic region | Mississippi-Ohio River valley region, midwest US including North Texas |
common mycological agar | Saboroud dextrose to inhbit growth of various bacteria |
difference btwn bacteria and fungal ribosomes | bacteria: 30 and 50S = 70S fungi: 80S = 40S + 60S |
examples of systemic mycoses | Coccidiodes, Histoplasma, Blastomyces, Penicillium |
blastoconidia | another name for the yeast cell; ex. Candida albicans |
risk factors for opportunistic mycoses like Cryptococcus and Pneumocystis | DM, lymphoma, HIV/AIDS, broad-spetrum abx, immunosuppressive tx, HOST GENE DEFECTS |
superficial and cutaneous mycoses | tinea versicolor, tinea capitis, tinea pedis, etc. |
subcutaneous mycoses | introduced through trauma to feet or legs, sometimes hands; ex. = sporotrichosis |
most important factors that can dictate pathogenicity of fungal infections | size of inoculum, whether or not there is a sufficient # of functional neutrophils/alveolar macrophages, ability of the fungus to go from mold form to yeast in human |
organisms that stain with GS for whatever reason | Candida and Cryptococcus, don't confuse them with bacteria |