Sketchy Micro: Cryptococcus Neoformans

Question 1

What cellular feature distinguishes Cryptococci?

Answer 1

They are “heavily encapsulated” (like the thick sarcophagi).

Question 2

What virulence factor is prominent in Cryptococcus?

Answer 2

Its capsule has a repeating polysaccharide sequence (like the design on the sarcophagus lid) that is antiphagocytic.

Question 3

How is Cryptococcus usually transmitted?

Answer 3

The spores are inhaled from pigeon droppings (like the archaeologist coughing from all the pigeon poop on the sarcophagi).

Question 4

What chemical test sets Cryptococcus apart from the other fungi?

Answer 4

It is urease-positive (like the archaeologist holding the bottle of ammonia).

Question 5

Cryptococcus usually presents in __________ patients.

Answer 5

immunocompromised (often AIDS)

Think of the cane held by the mummy.

Question 6

What clinical symptoms can Cryptococcus cause?

Answer 6

• Fever (archaeologist sweating)
• Pneumonia (he’s coughing)
• Meningitis (the archaeologist has a neck brace)

Question 7

What two tests can diagnose Cryptococcus?

Answer 7

Bronchoalveolar lavage followed by mucicarmine stain (in which the fungi will appear red) or methenamine silver stain (in which the fungi will appear silver).

(Think of the soap bubbles on the mummy’s chest, symbolizing bronchoalveolar lavage, and the red and silver sarcophagi.)

Question 8

Cryptococcus is often stained with _____________.

Answer 8

a negative-staining technique in which India ink makes a dark background; if C. neoformans is present, then it will be a pale circle with a halo around it

(Think of the vat of dark liquid with the pale bones sticking out of it.)

Question 9

One of the most sensitive tests for Cryptococcus infections is _______________.

Answer 9

the latex-agglutination test (like the archaeologist’s latex gloves next to the polysaccharide design –which is what the test detects)

Question 10

Cryptococcus meningitis will often display ____________ on MRI.

Answer 10

soap-bubble lesions (like the soap bubbles on the mummy’s head)

Question 11

What treats Cryptococcus meningitis?

Answer 11

It is a two-step therapy:
• 1: amphotericin B and flucytosine (like the hieroglyphics of frogs with the FLUte player)
• 2: fluconazole (like the pinecone on the pillar)