Yeast-like Fungi Flashcards
What does a germ tube look like and indicate?
No constriction at base the germ tube and positive indicates Candida albicans and Candida dubliniensis
Describe the Germ Tube Test.
2-3 hour incubation in rabbit plasma
Fermentation is _______ and requires gas production. Tubes must be acidic (yellow) AND produce gas to be considered positive.
anaerobic
What must be done to CHO tubes when testing for fermentation?
Tubes contain Durham tubes and must be oiled before incubating
Assimilation is ________ and commercial system used is the API 20C. CHO is used as a sole carbon source.
aerobic
What four yeasts do NOT have pseudohyphae on cornmeal?
Cryptococcus, Candida glabrata, Rhodotorula, and Saccharomyces
This is the #1 cause of yeast infections.
Candida albicans
This yeast is germ tube positive and has chlamydoconidia on cornmeal.
Candida albicans
This yeast has pseudohyphae on cornmeal and has a starburst appearance on the colony
Candida tropicalis
This yeast has dry colonies and show elongated blastoconidia (logs in the stream) on cornmeal agar.
Candida krusei
This yeast shows pseudohyphae on cornmeal and have a tangled, crooked appearance.
Candida parapsilosis
This yeast is common in diabetic urinary infections; often aggressive and difficult to treat due to resistance; no pseudohyphae; Trehalose positive.
Candida glabrata
This yeast is common in pulmonary and CNS infections (meningitis); associated with soil contaminated with pigeon, turkey, or chicken droppings (inhalation)
Cryptococcus
What is a major pathogen in AIDS patients (CNS)?
C. neoformans
Describe the appearance of Cryptococcus.
Thick mucopolysaccharide capsule gives the appearance of mucoid colonies; yeast cells appear larger and irregularly sized
What is used to detect cryptococcus?
Antigen detection (more sensitive than India Ink); urease positive; melanin positive (brown on birdseed); no pseudohyphae
Saccharomyces is ascospore _________. pos or neg?
positive (red)
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
What two yeasts are arthroconidia?
Trichosporon (white piedra) and Geotrichum
These colonies have a red or orange/red pigmentation and are seen where fluids are present or in moist environments.
Rhodotorula
What kind of reaction are you looking for on an API strip?
Cloudiness or turbidity
Cryptococcus is India Ink ______ in CSF which will form an outline around the capsule.
Positive
