Deck 14: Fungal Cultures

Question 1

Athlete's foot is considered a ________________ fungal infection.

A) superficial
B) cutaneous
C) subcutaneous
D) systemic

Answer 1

cutaneous

Question 2

Pneumocystis jiroveci, a yeast, is known for causing _____________mycosis.

A) cutaneous
B) subcutaneous
C) respiratory
D) systemic

Answer 2

respiratory

Question 3

The most important safety rule to follow in a mycology laboratory is to

A) prevent the aerosolization of the conidia of moulds.
B) not eat or drink in the laboratory.
C) disinfect benchtops daily.
D) use screw-top tubes.

Answer 3

prevent the aerosolization of the conidia of moulds.

Question 4

Processing hair for the presence of fungi requires

A) treatment with NALC to dissolve.
B) examination under a dissecting microscope.
C) cutting in small pieces prior to plating.
D) treatment using lysis-centrifugation.

Question 5

After centrifugation of a cerebrospinal fluid, the sediment is used for plating to fungal media. How should the supernatant be handled?

A) Discard it
B) Treat with NALC and plate to fungal media
C) Inject into a blood culture bottle
D) Use for serologic testing

Question 6

A physician sends skin scrapings for fungal stain and culture. The best means of direct examination of the specimen is

A) Gram stain.
B) KOH preparation.
C) India ink preparation.
D) Gomori methenamine silver stain.

Question 7

Which of the following stains is a fluorescent dye that binds specifically to cellulose and chitin?

A) Periodic acid-Schiff
B) Gomori methenamine silver
C) Calcofluor white
D) Giemsa

Question 8

India ink is used on body fluids to observe

A) arthroconidia.
B) ascospores.
C) pseudohyphae.
D) encapsulated yeast.

Question 9

Lactophenol cotton blue is used to

A) stain aerial mycelium of mould colonies for microscopic examination.
B) stain fungal walls in skin scrapings and tissues.
C) detect the cyst wall of Pneumocystis jiroveci in a bronchial alveolar lavage.
D) detect the presence of Histoplasma capsulatum in bone marrow smears.

Question 10

Which of the following media is used to observe the microscopic morphology of yeasts?

A) Sabouraud dextrose agar
B) Brain heart infusion agar
C) Potato dextrose agar
D) Cornmeal agar

Question 11

Dermatophyte test medium can help presumptively identify dermatophytes, such as Trichophyton spp., because

A) antibiotics present will only allow dermatophytes to grow.
B) it will turn from yellow to red with growth.
C) the addition of ammonium hydroxide prevents growth of other organisms.
D) it promotes the characteristic morphology of the organisms.

Question 12

Which medium promotes conversion of dimorphic fungi from the mould phase to the yeast phase?

A) Brain heart infusion with sheep blood
B) Sabouraud dextrose with brain heart infusion agar
C) Both a and b
D) Neither a nor b

Question 13

The ideal incubation temperature and atmosphere for fungal cultures is

A) 35°C CO₂
B) 35°C ambient air
C) 25°C CO₂
D) 30°C ambient air

Question 14

Using the image provided, this mould colony can be described as
Source: CDC and Dr. Libero Ajello

A) dematiaceous.
B) hyaline.
C) butyrous.
D) mucoid.

Question 15

Using the image provided, the fungal element observed is described as
Source: CDC and Dr. Libero Ajello

A) a germ tube.
B) dematiaceous septate hyphae.
C) hyaline aseptate hyphae.
D) conidiophores.

Question 16

Using the image provided, the fungal element observed is described as
Source: CDC and Dr. Libero Ajello

A) hyaline septate hyphae.
B) hyaline aseptate hyphae.
C) dematiacous septate hyphae.
D) dematiaceous aseptate pseudohyphae.

Question 17

Rapid identification of Cryptococcus neoformans includes

A) mucoid colony.
B) positive urease.
C) positive phenol oxidase.
D) all of the above. e. b and c.

Question 18

Using the image provided, the presumptive identification of this organism is

A) Candida glabrata
B) C. tropicalis
C) C. albicans
D) Cryptococcus neoformans

Question 19

A pinpoint colony that is rapid trehalose assimilation positive and appears as the image provided can be presumptively identified as

A) Cryptococcus neoformans.
B) Candida tropicalis.
C) C. albicans.
D) C. glabrata.

Question 20

Germ tube production is associated with

A) Candida tropicalis.
B) C. glabrata.
C) C. albicans.
D) Cryptococcus neoformans.