Medical Mycology III - Dimorphic Fungi Flashcards
Why did dimorphic fungi evolve?
Fungi were originally adapted to a cold, dark habitat. The bodies of animals are much warmer, so some fungi evolved to form a yeast form at warmer temperatures.
Beaver dams have been implicated in _______________.
Blastomyces infection
Dogs often get Blastomyces from _______________.
prairie dogs
In a healthy person, Blastomyces can cause _____________.
infiltrative pneumonia
Blastomyces most often gets into the body by ____________.
inhalation
What disease can Blastomyces cause that is not covered in the Sketchy scene?
Cutaneous infection
Blastomyces can form ___________ hyphae.
thin, septate
Blastomyces divides in a _______________ manner.
broad-based
_____________ prefers an arid climate.
Coccidioides
The “classic” Coccidioides is __________.
C. immitis
Lung cavitations and nodules are typical of ____________.
Coccidioidomycosis (often called “desert wind disease”)
______________ are spheroid and very large.
Coccidioidal spherules (the tumbleweed much larger than the RBC sombrero)
In general, laboratory culture of fungi grows the ____________ form.
cold, mold, spore-forming version
Alternating arthroconidia are _____________.
hyphae that have acellular interruptions that are suggestive of Coccidioides
Complement fixation predicts likelihood of ______________.
extrapulmonary Coccidioides
______________ overlaps the geographical distribution of Blastomyces.
Histoplasma
Question stems will commonly mention _____________ if they’re directing you to a diagnosis of Histoplasmosis.
caves (spelunking), chimneys (in which bats might have pooped), or chicken coops
______________ pneumonia is a classic sign of Histoplasmosis.
Shotgun
Blood cultures will not usually test positive even in fulminant ____________.
Histoplasmosis; antigen testing is more successful and quicker (like the red and yellow dripping stalactites!)
What length of antibiotics is typical of UTI treatment?
3 days
Although Sporothrix schenckii is found around the world, it is most common in _______________.
South America
Uniquely among the infectious fungi, Sporothrix is _______________.
usually transmitted by direct inoculation (as opposed to the usual inhalation)
Sporothrix is more common in _____________.
male adults and children of both sexes
Although uncommon, Sporothrix can ______________.
disseminate to the bones, joints, lungs, and meninges
True or false: Sporothrix can be detected through urine antigen screens.
False. There are no serologic tests for Sporothrix.
What four treatments can be given in Sporotrichosis?
- KI
- Terbinafine
- Itraconazole
- Amphotericin B
______________ is found only in Central and South America.
Paracoccidioides brasiliensis
P. brasiliensis occurs most often in _______________ workers.
agricultural workers on coffee farms
______________ seems to inhibit Paracoccidiodes.
Estrogen
What is the classic triad of Paracoccidioides?
- Edentulous (bad dental caries)
- COPD
- Cervical lymphadenopathy
Although treatment will annihilate Paracoccidioides, the _____________ will remain.
lung damage
________________ localizes to SE Asia.
Taloramyces (aka Penicillium) marneffei
T. marneffei is a ___________ fungi.
dimorphic
Under microscopy, Penicillium and Taloramyces look like ________________.
skeleton hands
What does this lecturer want you to know by the quote “Just because the water is calm doesn’t mean there are no crocodiles”?
In immunocompromised people, they might not have a fever or signs of infection but still have infection.
Why does BMT predispose people to Aspergillus infection?
BMT makes people temporarily neutropenic, and neutrophils are needed to kill Aspergillus because it is catalase-positive.
List the dimorphic fungi.
- Sporothrix schenckii
- Coccidioidomycosis
- Histoplasma
- Blastomyces
- Paracoccidioidomycosis
(“Some Can Have Both Phases”)
____________ has a cottony macroscopic appearance.
Blastomyces
The _____________ of Coccidioidomycosis are highly infectious.
arthroconidia
The incubation period of _____________ is long –up to 20 years.
P. brasiliensis
What is the best method for diagnosing an intracellular fungus?
Lysis-centrifugation culture
What pathology does mucor cause in IV drug users?
Skin abscesses at the site of infection with infarctive necrosis
The best way to treat a Candida UTI in an ICU patient is ________________.
removal of the catheter; medical treatment will usually just decrease the colony count, only for it to return soon after
True or false: Cryptococcus only causes disease in the immunocompromised.
False. Healthy people can get lung lesions (particularly common in the northwest).
