Fungi

Question 1

Cutaneous fungi (3)

Answer 1

1. Epidermophtyon
2. Microsporum
3. Trichophyton

Question 2

Subcutaneous fungi (5)

Answer 2

1. Actinomadura madurae
2. Cladosporium
3. Madurella grisea
4. Phialophora
5. Sporothrix schenckii

Question 3

Systemic fungi (4)

Answer 3

1. Blastomyces dermititidis
2. Coccidioides immitis
3. Histoplasma capsulatum
4. Paracoccidioides brasiliensis

Question 4

Opportunistic fungi (7)

Answer 4

1. Absidia corymbifera
2. Aspergillus fumigatis
3. Candida albicans
4. Cryptococcus neoformans
5. Pneumocysistis jiroveci
6. Rhizomicro pusillus
7. Rhizopus oryzae

Question 5

General characteristics of fungi (4)

Answer 5

• eukaryotic
• no chlorophyll (differ from plants)
• macroform (mushrooms, puff balls, gill fungi) v.s. microform (moulds and yeast)
• saprobes (live on dead/decaying organic matter)

Question 6

Non-dimorphic fungi

Answer 6

1. Aspergillus sp. (always in mycelial phase)

2. Torula sp. (always in yeast phase)

Question 7

KOH procedure (fungal identification)

Answer 7

1. Scrape from margin of lesion (Where younger cells are)
2. Place on slide
3. 2-3 drops 10% KOH (denatures proteins in human cells, leaves behind fungal cells)
4. Warm slide
5. 1 drop lactophenol cotton blue (optional step)
6. Add cover slip
7. Examine under high dry mag

Question 8

Candida albicans

Answer 8

• causes thrush

Question 9

Fungi in gram stain

Answer 9

• all fungi appear gram +

- in a stain with bacteria as well, fungi will be obviously bigger

Question 10

Intracellular Facultative fungi (4)

Answer 10

Blastomyces dermatitidis
Candida albicans
Coccidioides immitis
Histoplasma capsulatum

Question 11

Extracellular fungi (2)

Answer 11

Cryptococcus neoformans

Pneumocystis jirovecii

Question 12

Ascomyctonia/Ascomycota

Answer 12

• sexual spores (internal sac: ascus)

- asexual spores (borne externally as conidia)

Question 13

Aspergillus sp.

Answer 13

• non-dimorphic (always in mycelial phase)
• infection causes Aspergillosis (wide variety of diseases)
• inflicts damage upon host via PHYSICAL GROWTH through tissues (displacement/destruction of vital structures, i.e. angioinvasive Aspergillus)
• growth through tissues facilitates direct dissemination (in surface fluids, by flow of intestinal contents)
• no known degradative enzymes or exotoxins

Question 14

Aspergillus fumigatus

Answer 14

• inflicts damage upon host via use of a TOXIN (gliotoxin -inhibits macrophage phagocytosis, T-cell activation and induces apoptosis)

Question 15

Aspergillus flavus

Answer 15

• inflicts damage upon host via use of a TOXIN (aflatoxin - carcinogenic)