L23: Intro to Medical Mycology

Question 1

Mycotoxins

Answer 1

Toxins that affect humans on some level but don’t really cause disease

Question 2

Allergens

Answer 2

Cause allergies (many in air)

Question 3

Fungal cell

Answer 3

Typical eukaryotic cell but has cell walls and membrane sterol composition is ergosterol

Question 4

Fungal classification

Answer 4

1. Yeast
2. Mold
   Dimorphic = can exist as both

Question 5

Yeast characteristics

Answer 5

• -Unicellular
• -Reproduce by budding
• -Can form pseudohyphae (one can form a germ tube)

Question 6

Hyphae

Answer 6

Can group together to form mycelium (vegetative or aerial)

Question 7

Septa

Answer 7

Hairlike strands of mold that are long tubes

Question 8

Reproduction of molds

Answer 8

Asexual (prouce conidia, but call them spores anyway) or sexual (produce spores)

Question 9

Types of fungal infections

Answer 9

• -Superficial mycoses
• -Cutaneous mycoses
• -Subcutaneous mycoses
• -Systemic mycoses
• -Opportunistic mycoses

Question 10

Superficial mycoses

Answer 10

Infection of the outermost layers of skin and hair

Question 11

Cutaneous mycoses

Answer 11

Infection which extends into epidermis as well as hair and nails (common ones such as ringworm and athlete’s foot)

Question 12

Subcutaneous mycoses

Answer 12

Infections involving the dermis, subcutaneous tissues, muscle, and fascia

Question 13

Systemic mycoses

Answer 13

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

Question 14

Opportunistic mycoses

Answer 14

Infection associated primarily with immunosuppressed individuals

Question 15

Host response to fungal infection

Answer 15

• -Normally innate immune system is sufficient to prevent fungal infection
• -Traumatic implantation or inhalation can lead to infections
• -Severity depends on size of inoculum, magnitude of tissue destruction, ability to multiply, and immunologic status
• -Cell-mediated immunity is most important

Question 16

Antifungal drugs

Answer 16

• -Can be topical or systemic
• -Most common targets are cell wall and cell membrane (through direct membrane damage or prevention of ergosterol synthesis)

Question 17

Polyenes

Answer 17

Bind to membrane sterols to disrupt membrane

Question 18

What kind of antifungal agents inhibit ergosterol biosynthesis?

Answer 18

Azoles, allylamines, thiocarbamates, and morpholines

Question 19

Amphotericin B (polyene)

Answer 19

Used to be most widely used antifungal drugs, binds to ergosterol in membrane that causes pore to form

Question 20

Which types of antifungal drugs affect cell wall synthesis and how do they work?

Answer 20

Echinocandins (inhibits synthesis of B-glucan in cell wall)

Question 21

KOH prep

Answer 21

KOH dissolves skin cells/human cells faster than fungal cells

Question 22

All fungi stain ___.

Answer 22

Gram+

Question 23

India ink stain stains what particular fungi?

Answer 23

Cryptococcus neoformans

Question 24

Germ tube test is used for what generally?

Answer 24

Candida albicans