Medical Mycology III - Dimorphic Fungi Flashcards

1
Q

Why did dimorphic fungi evolve?

A

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.

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2
Q

Beaver dams have been implicated in _______________.

A

Blastomyces infection

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3
Q

Dogs often get Blastomyces from _______________.

A

prairie dogs

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4
Q

In a healthy person, Blastomyces can cause _____________.

A

infiltrative pneumonia

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5
Q

Blastomyces most often gets into the body by ____________.

A

inhalation

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6
Q

What disease can Blastomyces cause that is not covered in the Sketchy scene?

A

Cutaneous infection

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7
Q

Blastomyces can form ___________ hyphae.

A

thin, septate

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8
Q

Blastomyces divides in a _______________ manner.

A

broad-based

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9
Q

_____________ prefers an arid climate.

A

Coccidioides

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10
Q

The “classic” Coccidioides is __________.

A

C. immitis

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11
Q

Lung cavitations and nodules are typical of ____________.

A

Coccidioidomycosis (often called “desert wind disease”)

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12
Q

______________ are spheroid and very large.

A

Coccidioidal spherules (the tumbleweed much larger than the RBC sombrero)

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13
Q

In general, laboratory culture of fungi grows the ____________ form.

A

cold, mold, spore-forming version

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14
Q

Alternating arthroconidia are _____________.

A

hyphae that have acellular interruptions that are suggestive of Coccidioides

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15
Q

Complement fixation predicts likelihood of ______________.

A

extrapulmonary Coccidioides

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16
Q

______________ overlaps the geographical distribution of Blastomyces.

A

Histoplasma

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17
Q

Question stems will commonly mention _____________ if they’re directing you to a diagnosis of Histoplasmosis.

A

caves (spelunking), chimneys (in which bats might have pooped), or chicken coops

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18
Q

______________ pneumonia is a classic sign of Histoplasmosis.

19
Q

Blood cultures will not usually test positive even in fulminant ____________.

A

Histoplasmosis; antigen testing is more successful and quicker (like the red and yellow dripping stalactites!)

20
Q

What length of antibiotics is typical of UTI treatment?

21
Q

Although Sporothrix schenckii is found around the world, it is most common in _______________.

A

South America

22
Q

Uniquely among the infectious fungi, Sporothrix is _______________.

A

usually transmitted by direct inoculation (as opposed to the usual inhalation)

23
Q

Sporothrix is more common in _____________.

A

male adults and children of both sexes

24
Q

Although uncommon, Sporothrix can ______________.

A

disseminate to the bones, joints, lungs, and meninges

25
True or false: Sporothrix can be detected through urine antigen screens.
False. There are no serologic tests for Sporothrix.
26
What four treatments can be given in Sporotrichosis?
*  KI *  Terbinafine * Itraconazole * Amphotericin B
27
______________ is found only in Central and South America.
Paracoccidioides brasiliensis
28
P. brasiliensis occurs most often in _______________ workers.
agricultural workers on coffee farms
29
______________ seems to inhibit Paracoccidiodes.
Estrogen
30
What is the classic triad of Paracoccidioides?
*  Edentulous (bad dental caries) *  COPD *  Cervical lymphadenopathy
31
Although treatment will annihilate Paracoccidioides, the _____________ will remain.
lung damage
32
________________ localizes to SE Asia.
Taloramyces (aka Penicillium) marneffei
33
T. marneffei is a ___________ fungi.
dimorphic
34
Under microscopy, Penicillium and Taloramyces look like ________________.
skeleton hands
35
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.
36
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.
37
List the dimorphic fungi.
* Sporothrix schenckii *  Coccidioidomycosis *  Histoplasma *  Blastomyces * Paracoccidioidomycosis ("Some Can Have Both Phases")
38
____________ has a cottony macroscopic appearance.
Blastomyces
39
The _____________ of Coccidioidomycosis are highly infectious.
arthroconidia
40
The incubation period of _____________ is long – up to 20 years.
P. brasiliensis
41
What is the best method for diagnosing an intracellular fungus?
Lysis-centrifugation culture
42
What pathology does mucor cause in IV drug users?
Skin abscesses at the site of infection with infarctive necrosis
43
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
44
True or false: Cryptococcus only causes disease in the immunocompromised.
False. Healthy people can get lung lesions (particularly common in the northwest).