Mycology-General

Question 1

Mycology - Direct Examination - Calcofluor white:

• Mechanism (2)
• Highlights (3)

Answer 1

-Fluorochrome (UV Light)
-Binds cellulose and chitin in fungal cell wall
Highlights:
-Fungi
-Prototheca
-Acanthamoeba Cysts

Question 2

Stain for presumptive identification of Cryptococcus neoformans in CSF

Answer 2

India Ink

Question 3

Identification of of fungi in tissue sections. (2)

Answer 3

• GMS

- PAS

Question 4

Fungal culture:
-Usual media (3)

*Temperature/Duration

Answer 4

• Brain Heart Infusion (BHI) agar
• Sabouraud Dextrose agar
• Inhibitory Mold agar

*25-30C for 4-6 weeks

Question 5

Colony Morphology:

• Yeasts
• Molds

Answer 5

Yeast:
-Creamy or Mucoid

Molds:
-Fuzzy

Question 6

Dimorphic fungi definition.

Answer 6

Grow as Yeast at 37C

-Molds (septate hyphae) at 25-30C

Question 7

Hyaline Septate Molds:

-Definition

Answer 7

Hyphae with frequent septations

Question 8

Hyaline Septate Molds:

• Surface colonies
• Reverse side of plate

Answer 8

• White or colored

- Light

Question 9

Hyaline Septate Molds:

-Species (4)

Answer 9

• Aspergillus
• Penicillium
• Fusarium
• Dermatophytes (Epidermophyton, Microsporum, Trichophyton)

Question 10

Dermatiaceous Molds:

• Definition
• Plates

Answer 10

Septate mold that makes Melanin

-Surface and Reverse side of plate are both Dark

Question 11

Dermatiaceous Molds:

-Species (4)

Answer 11

• Alternaria
• P./S. boydii
• Scedosporium prolificans
• Curvularia

Question 12

Zygomycetes:

-Definition

Answer 12

Aseptate or Pauciseptate

Question 13

Zygomycetes:

• Growth
• Pigmented (+/-)
• Reverse side of plate

Answer 13

• Rapid growing (“Lid Lifters”)
• Pigmented, NOT melanin
• Light (reverse side)

Question 14

Zygomycetes:

-Species (4)

Answer 14

• Rhizopus
• Mucor
• Cunninghamella
• Rhizomucor

Question 15

Yeast - Colony Morphology:

-Cryptococcuss pp.

Answer 15

Mucoid colonies (+/-)

Question 16

Yeast - Colony Morphology:

-Candida albicans

Answer 16

“Feet” or starlike projections

Question 17

Yeast - Blastoconidia only:

-Important Examples (4)

Answer 17

• Cryptococcus
• C. glabrata
• Rhodotorula
• Malassezia

Question 18

Yeast - Blastoconidia w/ Pseudohyphae:

-Important Examples (2)

Answer 18

• Candida spp. (Except glabrata)

- Saccharomyces cerevisiae

Question 19

Yeast - Arthroconidia:

-Important Examples (2)

Answer 19

• Trichosporon

- Geotrichum

Question 20

Thermally Dimorphic Fungi. (6)

Answer 20

• Histoplasma capsulatum
• Blastomyces dermatitidis
• Coccidiodes immitis/posadasii*
• Paracoccidioides brasillensis
• Sporothrix schenkii
• Penicillium marnefii

*Produces same structures (septate hyphae/arthroconidia) at 25C or 37C; Produces Spherules in tissue and at 37C.