8.15_Fungal and Antifungals Flashcards
(25 cards)
True pathogens
fungi capable of infecting a healthy individual or immunocompetent
opportunistic pathogens
fungi capable of infecting an immunocompromised individual
Characteristics of Fungi
80s ribosomes like human, DNA RNA, cell wall of chitin, cell membrane, yeasts are unicellular and molds are multicellular, have protein mitochondria and nucleus
Yeast uni or multi?
Mold uni or multicellular?
Yeast are uni and mold are multi
Septate Hyphae versus Aseptate Hyphae
Septate has walls between mold cells
Aseptate means no walls between cells
Conidia
exomorphic spores that are inert, so must grow into another mold cell to be active, always on molds
Candida spp.
medically important yeast infection, will lead to thrush or biofilm on the tongue and oral cavity, it cannot turn into mold so it is only a yeast and not dimorphic, rash is common in babies with low immune function and diaper rash
Aspergillus
mold always, septate hyphae
Zygomycetes (Mucor and Rhizopus)
mold always, serious infection, aseptate hyphae, often in immunocompromised
Thermally dimorphic fungi info
grow as molds in environment where they make spores that can be inhaled, once inhaled the spores lead to active fungi which are thermally changed to a yeast in the host
Ergosterol
similar to cholesterol in human cell membranes, is the sterol in fungal cell membranes
B1,3 glucans
in the cell wall of fungals, unique to fungals
Mannose containing proteins on surface
proteins that have mannose assoicated with them, these are not targeted by antifungals but they are used for immune recognition
Polyenes
antifungal, binds ergosterol and forms pores in the membranes, works on yeasts, molds and dimorphics
Azoles
antifungal, prevents synthesis of the ergosterol so membrane cannot grow and function properly , works on yeasts, molds, and dimorphics
Echinocandins
antifungal, inhibit synthesis of B glucans that are associated with the cell wall, works on yeasts and molds
5-Flucytosine
antifungal, is a pyrimidine analog, inhibits thymidine synthesis therefore stopping growth of fungus, DNA target and protein synthesis inhibitor, it only works on yeasts
Candida albicans
yeast cell, round, makes germ tubes which are half hearted attempts at septate hyphae, very common in practice
Cryptococcus neoformas
yeast, common, polysaccharide capsule, see with india ink that capsule excludes
Aspergillus
mold, common, septate hyphae
Mucor and Rhizopus
mold, common, aseptate hyphae, high mortality
Endemic mycoses
means fungi that are widely present in a specific area and can infect immunocompetent people, closer to being a true pathogen, but it is more likely to infect immunocompromised individuals
These can remain latent in a immunocompetent individual until they are compromised and then it may show symptomatic infection
Histoplasma Capsulatum
true pathogen, dimorphic, endemic mycoses, from bat guano, mainly in mideast region including high conc in tennessee and ohio, mold in environment leads to inhaled spores that turn into yeast infection in host
Blastomyces dermatitidis
true pathogen, dimorphic, endemic mycoses, all over south and midwest, most northern of three we have studied, most likely to be inhaled, but this one can enter through abrasions in the skin, shows in lung and can lead to dermal and MSK problems
