Yeast-like Fungi

Question 0

What does a germ tube look like and indicate?

Answer 0

No constriction at base the germ tube and positive indicates Candida albicans and Candida dubliniensis

Question 1

Describe the Germ Tube Test.

Answer 1

2-3 hour incubation in rabbit plasma

Question 2

Fermentation is _______ and requires gas production. Tubes must be acidic (yellow) AND produce gas to be considered positive.

Answer 2

anaerobic

Question 3

What must be done to CHO tubes when testing for fermentation?

Answer 3

Tubes contain Durham tubes and must be oiled before incubating

Question 4

Assimilation is ________ and commercial system used is the API 20C. CHO is used as a sole carbon source.

Answer 4

aerobic

Question 5

What four yeasts do NOT have pseudohyphae on cornmeal?

Answer 5

Cryptococcus, Candida glabrata, Rhodotorula, and Saccharomyces

Question 6

This is the #1 cause of yeast infections.

Answer 6

Candida albicans

Question 7

This yeast is germ tube positive and has chlamydoconidia on cornmeal.

Answer 7

Candida albicans

Question 8

This yeast has pseudohyphae on cornmeal and has a starburst appearance on the colony

Answer 8

Candida tropicalis

Question 9

This yeast has dry colonies and show elongated blastoconidia (logs in the stream) on cornmeal agar.

Answer 9

Candida krusei

Question 10

This yeast shows pseudohyphae on cornmeal and have a tangled, crooked appearance.

Answer 10

Candida parapsilosis

Question 11

This yeast is common in diabetic urinary infections; often aggressive and difficult to treat due to resistance; no pseudohyphae; Trehalose positive.

Answer 11

Candida glabrata

Question 12

This yeast is common in pulmonary and CNS infections (meningitis); associated with soil contaminated with pigeon, turkey, or chicken droppings (inhalation)

Answer 12

Cryptococcus

Question 13

What is a major pathogen in AIDS patients (CNS)?

Answer 13

C. neoformans

Question 14

Describe the appearance of Cryptococcus.

Answer 14

Thick mucopolysaccharide capsule gives the appearance of mucoid colonies; yeast cells appear larger and irregularly sized

Question 15

What is used to detect cryptococcus?

Answer 15

Antigen detection (more sensitive than India Ink); urease positive; melanin positive (brown on birdseed); no pseudohyphae

Question 16

Saccharomyces is ascospore _________. pos or neg?

Answer 16

positive (red)

Question 17

This yeast requires fatty acids (virgin olive oil) for growth; looks like spaghetti and meatballs; associated with systemic infections such as hyperalimentation (patients getting nutrients containing high amount of lipids)

Answer 17

Malassezia furfur

Question 18

What two yeasts are arthroconidia?

Answer 18

Trichosporon (white piedra) and Geotrichum

Question 19

These colonies have a red or orange/red pigmentation and are seen where fluids are present or in moist environments.

Answer 19

Rhodotorula

Question 20

What kind of reaction are you looking for on an API strip?

Answer 20

Cloudiness or turbidity

Question 21

Cryptococcus is India Ink ______ in CSF which will form an outline around the capsule.

Answer 21

Positive