fungi Flashcards
gen fungi traits
eukaryotic
strict aerobes (except brewer/baker yeast)
defined nuc.
cell membrane has ergosterol instead of cholesterol
cell walls have chitin, mannan, and glucan
gen. traits of yeasts/molds
both can cause disease in humans
yeast: unicellular, bud/use binary fission, have pseudomycelium
mold - filamentous w/ hyphae
a hyphal mass is called ______, when it has cross walls it’s called ______ without cross walls it’s _______
mycelium - hyphal mass
septate - w/ cross walls
coenocytic - w/o cross walls
2 fungal encounter mechanisms
- incidental environmental contact - high inoculum or immunosuppression needed
- normal human flora - esp yeasts, cause infection in immunocomp.
bodily fungi responses
skin/natural barriers: low pH, desiccation, ep. turnover, microflora and fatty a’s
infections contained by neutrophil phagocytosis
infections eliminated by t cell mediated immunity
diff btwn endemic and opportunistic funge?!?
endemic: restricted geographically, true pathogens result in systemic infections in healthy people
opportunistic: fungi aren’t true pathogens, cause systemic infect. in immunocompromised patients
endemic fungal diseases
histoplasmosis
blastomycosis
coccidiodomycosis
histoplasmosis traits
geographically bound to mid-southeastern US
soil organism
have spores get inhaled then transform to yeast phase once they pass mucosal barriers
histoplasmosis spreads through the _____. causes a _________ system infection and avoids phagocytosis by ______
lymph
reticuloendothelial
modiffying pH and removing growth factors of phagocytic cell
extensive exposure to histoplasmosis can result in ______. the body eradicates it via ________
pneumonia
T lymphocytes
blastomycosis region and environment
mississippi river valley/SE USin soil/decaying wood
bastomyces’ conidia (spores and filaments) enter through _____ and transform into _________ with _________ buds. and are dealt with by ________
inhalation
thick walled yeasts
single, broad based buds
phagocytosis
how is Blastomyosis is similar to histoplasmosis?
presents as pneumonia and skin lesions (like disseminated histoplasmosis)
controlled by cell-mediated immunity
organism can remain viable for a long time
coccidiodomcosis habitat
burrows of desert animals
in southwestern US
how do coccidiodes enter?
inhaled,
unlike histo/blasto transform into spherules filled w/ endospores
also unlike histo/blasto transformation isn’t temp dependant
spherules resist phagocytosis
coccidiodes disease characteristics
targets lunges/but can spread to pulmonary infection
causes desert rheumatism and skin nodules from host response
disseminated coccidiodomycosis can lead to
chronic meningitis that needs life time antifungal therapy
how do you treat coccidiodomycosis?!?
polyenes - lipophilic bind to ergosterol
Azoles - stops ergosterol synth, esp itraconazole
what leads to recurrent/disseminated infections with endemic fungi?
granulomas
opportunistic mycoses diseases
candidiasis cryptococcosis aspergillosis mucormycosis pneumocytosis
candida environment
endogenous (microflora)
in GI/repro tracts
what’s special about kidney structure
has dimorphism; can have mycelial form or yeast form
candida infection locations and severity
can be mucosal, cutaneous, or systemic and all can be life threatening
candidiasis can present itself as…
thrush- thick white lesions or mucosa
intertriginous candidiasis - diaper rash
disseminated infection
traits of cryptococcus neoformans
yeast found in soil
produces lg. capsule in tissues but not environment
grows well @ body T
cryptococcosis infection traits ?!?
in immunocompromised
can cause pulmonary infection - pneumonia
disseminated - can enter CNS and cause meningitis and brain abscesses
virulence factors of cryptococcosis
capsule = prevents phagocytosis
melanin - enhances cell wall
fungi that cause pulmonary infection
cryptococcus
aspergillus
mucormycosis
pneumocystis
aspergillus environment and entry?!?
ubiquitus
inhaled and turn into hyphae that invade thru blood vessel walls
aspergillus damage
causes abscesses and necrotic skin lesions
can cause allery/asthma
can cause pneumonia
has toxic metabollitic products- alphatoxins and phospholipase
mucormycosis infection is similar to_______ and has two clinical manifestations….
aspergillus
- rhinocerebral form- diabetic specific (attacks face)
- disseminated mucormycosis - pulmonary lesions
not much is known about pneumocystis but it’s restricted to ______ and causes ______
lungs
pneumonia
most common fungal infections in humans are clinical diseases called ______ which are a type of _______
tineas (ring worm/athletes foot) - type of dermatophyte
examples of superficial mycoses
seborrheic dermatitis- greasy scales in facial hair/scalp
tinea versicolor - pigmented skin patches
dermatophyte risk factor and requirements?!?
hanging out with kids, need to have skin trauma and continuous moist conditions
what’s common btwn subcutaneous and superficial fungal infections?
locallized
need immunocompromised person
examples of antifungals are______ and _____
allylamines - block ergosterol synth
echinocandins - inhibit beta glucan synth
