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Flashcards in Yeast-like Fungi Deck (22):
0

Describe the Germ Tube Test.

2-3 hour incubation in rabbit plasma

1

What does a germ tube look like and indicate?

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

2

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

anaerobic

3

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

Tubes contain Durham tubes and must be oiled before incubating

4

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

aerobic

5

What four yeasts do NOT have pseudohyphae on cornmeal?

Cryptococcus, Candida glabrata, Rhodotorula, and Saccharomyces

6

This is the #1 cause of yeast infections.

Candida albicans

7

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

Candida albicans

8

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

Candida tropicalis

9

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

Candida krusei

10

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

Candida parapsilosis

11

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

Candida glabrata

12

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

Cryptococcus

13

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

C. neoformans

14

Describe the appearance of Cryptococcus.

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

15

What is used to detect cryptococcus?

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

16

Saccharomyces is ascospore _________. pos or neg?

positive (red)

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)

Malassezia furfur

18

What two yeasts are arthroconidia?

Trichosporon (white piedra) and Geotrichum

19

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

Rhodotorula

20

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

Cloudiness or turbidity

21

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

Positive