IASM 61: Fungi

Question 1

What are the components of Fungi cell wall

Answer 1

Glucan 60%
Protein 30%
Chitin 10%

Question 2

What is the major component of fungi cell membrane

Answer 2

Ergosterol

Question 3

What stain is used to stain Cryptococcus neoformans

What is special about the stain

Answer 3

Indian Stain
Negative stain (stains the background)

Question 4

What are fungi (multicellular) called
How do they reproduce?
What do they form? _____
Name 2 examples of them

Answer 4

Mould
Spores (both sexual and asexual reproduction)
Form hyphae => Mycelium
Aspergillus fumigatus, Dermatophytes

Question 5

What are dimorphic fungi

Name an example

Answer 5

Yeasts at 37C, Moulds at 25C
Talaromyces marneffei

(37C 熱死 = ‘Yeast’)

Question 6

What are fungi (unicellular) called
How do they reproduce?
Name 2 examples of them

Answer 6

Yeast
Budding
Candida albicans, Cryptococcus neoformans

Question 7

HIV infection will increase the chance of infection from which 2 fungi?

Answer 7

Cryptococcus neoformans

Talaromyces marneffei

Question 8

Consider Candidiasis
Name the fungi that causes this disease
Name 2 clinical features of this disease

Answer 8

Consider Candidiasis
Name the fungi that causes this disease- Candida albicans
Name 2 clinical features of this disease- Oral thrush, Vaginal thrush

Question 9

Consider Dermatophytosis
Name the fungi that causes this disease
Name 3 clinical features of this disease

Answer 9

Consider Dermatophytosis
Name the fungi that causes this disease- Dermatophytes

Name 2 clinical features of this disease:
Tinea pedis (foot)
Tinea capitum (hair)
Tinea unguium (nails)

Question 10

How do we visualize fungi

• KOH smear can visualize…
• Gram smear can visualize…
• Indian ink smear can visualize…

Answer 10

How do we visualize fungi

• KOH smear can visualize moulds
• Gram smear can visualize candida
• Indian ink smear can visualize cryptococcus neoformans

Question 11

Name a component of the cell wall of aspergillus fumigatus

Answer 11

Galactomannan

Question 12

What fungi can nucleic acid detect

Answer 12

Aspergillus fumigatus

Question 13

Anti-fungal agents

What is the function of Echinocandins (e.g. Caspofungin, Micafungin)

Answer 13

Inhibit Cell Wall Synthesis

Question 14

Anti-fungal agents

What substance causes the inhibition of cell wall synthesis

Answer 14

Echinocandins

e.g. Caspofungin, Micafungin

Question 15

Anti-fungal agents

What is the function of Polyenes (e.g. Nystatin, Amphotericin B)

Answer 15

Complex with ergosterol to disrupt fungal membrane

Polyene -> Polymer -> Complex

Question 16

Anti-fungal agents

What is the function of Azoles (e.g. Fluconazole, Itraconazole)

Answer 16

Inhibit ergosterol synthesis

Question 17

Anti-fungal agents

What substance causes the inhibition of DNA synthesis

Answer 17

5-flucytosine (Nucleoside analogue)

Question 18

Anti-fungal agents

What does 5-flucytosine (Nucleoside analogue) do to fungi

Answer 18

Inhibit DNA synthesis

Question 19

What is the reservoir of Candidas albicans

Answer 19

Skin
GI tract
Female genital tract
(endogenous infection)

Question 20

Is it possible to avoid exposure to candida albicans

Answer 20

No (endogenous infection)

Question 21

Treatment options for Candidiasis

• Superficial Candidiasis: Name 2
• Systemic Candidiasis: Name 2

Answer 21

Treatment options for Candidiasis

• Superficial Candidiasis: Nystatin (Polyene)/ Fluconazole (Azole)
• Systemic Candidiasis: Amphotericin B (Polyene)/ Fluconazole (Azole)