Mycology

Question 1

What is the main sterol in fungal cell walls?

Answer 1

Ergosterol

Question 2

What comprises the fungal cell wall?

Answer 2

1. Chitin2. a-glucan3. B-glucan4. Mannan5. Cellulose6. Chitosan

Question 3

What is the structure of the fungal cell wall?

Answer 3

1. Typical phospholipid bilayer2. Unique sterol composition - ergosterol

Question 4

What are the properties of yeast?

Answer 4

1. Unicellular - spherical or ellipsoid shape2. Reproduce via budding3. Can form pseudohyphae or germ tubes

Question 5

What structure is diagnostic for Candida albicans?

Answer 5

Germ tube

Question 6

What are properties of molds?

Answer 6

1. Hyphae (mycelium - vegetative or aerial)2. Septa3. Asexual and sexual reproduction

Question 7

What is a mycelium?

Answer 7

A cluster of hyphae

Question 8

What type of mold reproduction involves conidia?

Answer 8

Asexual

Question 9

What type of mold reproduction involves spoers?

Answer 9

Sexual

Question 10

What are the types of fungal infections?

Answer 10

1. Superficial 2. Cutaneous3. Subcutaneous4. Systemic5. Opportunistic

Question 11

What are properties of superficial mycoses?

Answer 11

Outermost layer of skin and hair

Question 12

What are properties of cutaneous mycoses?

Answer 12

Infection which extends deep into the epidermis as well as invasive hair and nail infections

Question 13

What are properties of subcutaneous mycoses?

Answer 13

Infections involving the dermis, subcutaneous tissues, muscle, fascia

Question 14

What are properties of systemic mycoses?

Answer 14

Infections that originate primarily in the lung but may spread to any organ

Question 15

What are properties of opportunistic mycoses?

Answer 15

Infection associated primarily with immunosuppressed individuals

Question 16

What factors contribute to severity of fungal disease?

Answer 16

1. Size of inoculum2. Magnitude of tissue destruction3. Ability of fungi to multiply in tissues4. Immunologic status of host

Question 17

What type of immunity is essential for controlling and eliminating fungal infection?

Answer 17

Cell mediated immunity

Question 18

What are the main methods to target the cell membrane pharmacologically?

Answer 18

1. Direct damage via polyenes2. Inhibit ergosterol synthesis

Question 19

What are the properties of antifungal drugs?

Answer 19

1. Inhibit ergosterol synthesis2. Polyenes bind to membrane sterols 3. Azoles, allylamines, thiocarbamates, and morpholines inhibit ergosterol synthesis

Question 20

What type of compound is Amphotericin B?

Answer 20

1. Polyene2. Binds to ergosterol in the membrane and causes a pore to form, leading to osmotic disruption

Question 21

What are properties of echinocandins?

Answer 21

1. Inhibit B-glucan synthesis2. Highly selective 3. Used mainly against Candida and Aspergillus

Question 22

How are fungi diagnosed?

Answer 22

1. Visually2. Colony morphology and hyphal spore structures

Question 23

What does the KOH preparation diagnose?

Answer 23

1. To examine hair, nail, skin, fluids, exudates, biopsies2. To visualize hyphae, large yeast, spherules, sporangia

Question 24

What do chlorazol black and calcofluor white stain?

Answer 24

Carbohydrate rich cell wall

Question 25

The carbohydrate rich cell wall of fungi can be stained by what?

Answer 25

1. Chlorazol black2. Calcofluor white

Question 26

Are fungi gram positive or gram negative?

Answer 26

All fungi are gram positive

Question 27

What does a positive India ink test indicate?

Answer 27

Presence of Cryptococcus neoformans

Question 28

Cryptococcuz neoformans will stain positive with which stain?

Answer 28

India ink stain