Fungi Flashcards
A true pathogen is…
capable of infecting healthy individuals
An opportunistic pathogen…
infects immunocompromised individuals
Cell wall of fungi is made of ___ and ___
chitin; beta glucans
Why are antifungals more toxic?
Fungi are more genetically similar to us than bacteria or viruses, so drugs are less selective.
Explain how a fungus can be “thermally dimorphic.”
At lower temps (i.e. ambient environment), mold forms with hyphae and produces spores, but is relatively inert. Spores can be inhaled, and the higher temperature of human body triggers the infectious yeast form.
Spores are also known as…
conidia
2 kinds of mold hyphae
septate and aseptate
Yeast cells with polysaccharide capsules tend to cause…
pneumonia and meningitis
Yeast buds via…
mitosis
Candida spp causes…
oral candidiasis (thrush)
Aspergillus is a ____ with ____ hyphae.
mold; septate
Zygomycetes is a ____ with ____ hyphae.
mold; aseptate
Best known zygomycete is ___, and it causes ___
mucor; rhinocerebral mucormycosis
Spore infection can happen via ___ and ___
inhalation; breaks in skin
Cell membranes of fungi contain ___ instead of cholesterol
ergosterol
Surface proteins of fungi contain…
mannose/mannoproteins
What are the 3 main classes (by MOA) of antifungals?
cell wall active agents; beta-glucan synthesis inhibitors; DNA/protein synthesis inhibitors
Polyenes MOA?
bind ergosterol and form pores in membrane/insert into membrane
Polyenes can be toxic because they …
also bind cholesterol in mammalian cells
Azoles MOA?
inhibition of ergosterol synthesis
Echinocandins MOA?
beta-glucan synthesis
5-Flucytosine (5-FC) MOA?
Pyrimidine analogue that inhibits thymidine synthesis and subsequently inhibits DNA and protein synthesis
Echinocandins are targeted to…
yeast
Candida albicans forms ____ (not a thermal response)
germ tubes
Are mucor and rhizopus opportunistic or true fungi?
opportunistic
Histoplasma capsulatum/Histoplasmosis is contracted from _____ and is endemic in ____
bat guano; the midwest US
Blastomyces dermatitidis/Blastomycosis is contracted from _____ and is endemic in _____
soil/open wounds; eastern US
Coccidioides immitis/Valley Fever is contracted from ____ and is endemic in ____
aerated spores; SW US
Dimorphic fungi are also known as ____
endemic fungi
