Flashcards in Mycology Deck (28):
What is the main sterol in fungal cell walls?
What comprises the fungal cell wall?
1. Chitin2. a-glucan3. B-glucan4. Mannan5. Cellulose6. Chitosan
What is the structure of the fungal cell wall?
1. Typical phospholipid bilayer2. Unique sterol composition - ergosterol
What are the properties of yeast?
1. Unicellular - spherical or ellipsoid shape2. Reproduce via budding3. Can form pseudohyphae or germ tubes
What structure is diagnostic for Candida albicans?
What are properties of molds?
1. Hyphae (mycelium - vegetative or aerial)2. Septa3. Asexual and sexual reproduction
What is a mycelium?
A cluster of hyphae
What type of mold reproduction involves conidia?
What type of mold reproduction involves spoers?
What are the types of fungal infections?
1. Superficial 2. Cutaneous3. Subcutaneous4. Systemic5. Opportunistic
What are properties of superficial mycoses?
Outermost layer of skin and hair
What are properties of cutaneous mycoses?
Infection which extends deep into the epidermis as well as invasive hair and nail infections
What are properties of subcutaneous mycoses?
Infections involving the dermis, subcutaneous tissues, muscle, fascia
What are properties of systemic mycoses?
Infections that originate primarily in the lung but may spread to any organ
What are properties of opportunistic mycoses?
Infection associated primarily with immunosuppressed individuals
What factors contribute to severity of fungal disease?
1. Size of inoculum2. Magnitude of tissue destruction3. Ability of fungi to multiply in tissues4. Immunologic status of host
What type of immunity is essential for controlling and eliminating fungal infection?
Cell mediated immunity
What are the main methods to target the cell membrane pharmacologically?
1. Direct damage via polyenes2. Inhibit ergosterol synthesis
What are the properties of antifungal drugs?
1. Inhibit ergosterol synthesis2. Polyenes bind to membrane sterols 3. Azoles, allylamines, thiocarbamates, and morpholines inhibit ergosterol synthesis
What type of compound is Amphotericin B?
1. Polyene2. Binds to ergosterol in the membrane and causes a pore to form, leading to osmotic disruption
What are properties of echinocandins?
1. Inhibit B-glucan synthesis2. Highly selective 3. Used mainly against Candida and Aspergillus
How are fungi diagnosed?
1. Visually2. Colony morphology and hyphal spore structures
What does the KOH preparation diagnose?
1. To examine hair, nail, skin, fluids, exudates, biopsies2. To visualize hyphae, large yeast, spherules, sporangia
What do chlorazol black and calcofluor white stain?
Carbohydrate rich cell wall
The carbohydrate rich cell wall of fungi can be stained by what?
1. Chlorazol black2. Calcofluor white
Are fungi gram positive or gram negative?
All fungi are gram positive
What does a positive India ink test indicate?
Presence of Cryptococcus neoformans