Yeast, Cryptococcus, Trichosporon, Rhodotorula, Geotrichum, & Malassezia

Here is a ChromAgar plate. ID the green yeast

Candida albicans

Here is a ChromAgar plate. ID the blue yeast

Candida tropicalis

Here is a ChromAgar plate. ID the pink yeast

Candida crusei

What agar and temperature is used to typically culture for yeast?

SABHI at 22-30°C

Below is an image of a germ tube result. ID the organism

Candida albicans

TRUE or FALSE. This result is for Candida albicans

FALSE

ID the type of yeast

Candida glabrata

ID the type of yeast

Candida tropicalis

ID the type of yeast

Candida krusei

ID the type of yeast

Candida parapsilosis

ID the type of yeast

Candida parapsilosis

What is the only candida species that is urease positive?

Candida krusei

This type of yeast species can cause

• Ora Thrush

• Vaginal Yeast

• Nail infections (onychomycosis)

• Cuticle infections (paronychomycosis)

• Diaper rash

• Systemic infections (meningitis, UTI, heart & lung infections)

Candida albicans

Which two yeast species are germ tube positive?

Candida albicans & Candida dubliniensis

On a cornmeal tween 80 agar colonies were observed that looked like sagebrush with large hyphae with blastoconidia not being present. Which yeast species is this?

Candida parapsilosis

On a cornmeal tween 80 agar colonies were observed with highly compacted blastoconidia and no pseudohyphae or hyphae. What yeast species is this?

Candida glabrata

Colonies grew on a bird seed agar plate and were inoculated onto a urea slant. The next day the urea slant turned pink which was positive for producing urease. ID the organism

Cryptococcus

How is cryptococcus neoformans acquired?

• Contact with bat, pigeon, or other bird droppings

• Contaminated vegetables, fruits, and milk

What type of specimens can be performed for direct antigen test for cryptococcal antigen?

CSF or Serum

TRUE or FALSE. Cryptococcus is positive for phenol oxidase

TRUE

TRUE or FALSE. Does cryptococcus utilize inositol?

TRUE

TRUE or FALSE. Cryptococcus is negative for nitrate reduction

TRUE

ID this yeast like fungus

Geotrichum candidum

ID this yeast

Rhodotorula spp

Is Rhodotorula inositol negative or positive?

Negative

Where is Rhodotorula spp found?

• Moist environments (ex. shower curtains, toothbrushes)

• Soil

• Dairy products

ID this species

Trichosporon spp hW

What type of infections is Trichosporon related to?

human hair aka white piedra i

TRUE or FALSE. Trichosporon is positive for urease

TRUE

ID this species

Malassezia spp

What is added to agar to help malassezia spp grow better?

Olive oil

ID this species

Saccharomyces cerevisiae

The growth of yellow-white yeast colonies with a smooth or hair-like structure within 2-3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Observation of colonies are growing on cornmeal agar. Note the “logs in-steam” arrangement of elongated blastoconidia.What is the ID of the yeast?

Candidia kefyr