Fungi Flashcards
What is a primary pathogen?
Pathogen that can cause disease in anybody.
What is an opportunistic pathogen?
Pathogen that causes disease in the immunocompromised but has low pathogenicity in all other demographics.
What are 2 characteristic substances found in cell walls of fungi?
Chitin & ergosterol.
Why is chitin important?
It stains white with calcium binding agents so we can identify fungi in clinical specimens very easily.
Why is ergosterol important?
Humans have cholesterol in our cell membranes, so ergosterol will differentiate fungal cells from human cells. Many antifungal agents target ergosterol synthesis.
What are the 3 important fungi to remember?
Molds, yeasts & thermally dimorphic fungi.
What is the body of a mould called?
The thallus.
What are the 2 types of hyphae?
Coenocytic & septate.
What is the difference between coenocytic hyphae and septate hyphae?
Septate hyphae have many nuclei that are separated by septations. Coenocytic hyphae have many nuclei that lack septations.
Most moulds are ________ _______, while most yeasts are _____________ ________ which is important for invasiveness.
obligate aerobes, facultatively anaerobic.
The shape of yeast is _____/_________ - it looks like _______ bacteria.
oval/spherical, larger.
How do yeasts reproduce?
Budding.
What happens when the buds of yeast fail to detach?
They form pseudohyphae.
Saccharomyces is a ___-_________ yeast used for cooking, baking & fermentation.
non-pathogenic.
What is the most common yeast causing human infections?
Candida albicans.
Why are yeasts generally more invasive to the human body than moulds are?
Yeasts are facultatively anaerobic, so they can survive in areas of our body that have anaerobic environments.
What is the virulence factor of Cryptococcus neoformans?
Polysaccharide capsule.
What are the 2 forms of growth for thermally dimorphic fungi & at what temperature does each form occur at?
Mould @ 20ºC.
Yeast @ 37ºC (body temp).
Thermally dimorphic fungi are always _______ pathogens.
primary.
Are infections by thermally dimorphic fungi infections from person-to-person? Why or why not?
No, the mould form can only be spread by spores in the air.
Describe the pathogenicity of Sporothrix (Rose Gardener’s Disease).
Fungal spores introduced into wound after trauma → enter bloodstream → reach lymph nodes & cause lymphangitis.
What are fungal “spores” technically called?
Conidia.
Fungi are generally ____ nutritionally demanding than bacteria & grow ______ than bacteria in extreme conditions.
less, better.
What are all fungal diseases called?
Mycoses.
