Mycology (fungi) Flashcards
1
Q
3 key points about Fungi
A
- Nosocomial infections
- Opportunistic infections
- Few are primary pathogens
2
Q
Chitin
A
Used to create the cell wall in fungi
- “Calcofluor white” when stained with calcium
3
Q
Ergosterol
A
Sterol in fungi cell membrane (human equiv = cholesterol)
- Regulates passage of molecules through membrane
- Antifungal drugs (Amphotericin B) aim to affect ergosterol synthesis
4
Q
Describe the types of fungi
A
Mold, Yeast, Thermally dimorphic
5
Q
Mold
A
- Body of fungus/masses of hyphae = “thallus”
- ex. Aspergillus
6
Q
Yeast
A
- Reproduces by budding
- “Pseudohyphae” when it fails to detach
- Ex. Candida albicans invades as pseudohyphae - Can be non-pathogenic
- Ex. Saccharomycens (ethanol for wine, CO2 for bread) - Capable for facultative anaerobic growth
* Important for invasiveness
7
Q
What is Cryptococcus neoformans and its virulence factor?
A
- A yeast
- VF: polysaccharide capsule
8
Q
Thermally dimorphic fungi
A
- Can grow as mold (20C) or yeast (37); temperature dependent
- Ex. Sporothrix (rose gardener’s disease)
9
Q
Sporothrix
A
Rose Gardener’s Disease
- Subcutaneous infection by a dimorphic fungi
- Fungal spores are introduced into wound after trauma
- Commonly results in lymphangitis on arms + legs
- Causes ulcer formations as it progresses
10
Q
How do bacteria reproduce?
A
Formation of spores called “conidas”
- Also important for identification
11
Q
Nutritional demands of fungi
A
- Less nutritionally demanding than bacteria
- Grow better than bacteria in extreme conditions
- Most are aerobic + grow best @25-30C
12
Q
Mycosis (pl. mycoses)
A
Fungal diseases
13
Q
Superficial mycoses
A
- Infects the surface of hair shafts + outer skin layer
- Mild infections: Black & White Piedra; Malassezia furfur
14
Q
Cutaneous mycoses
A
- Infects deeper layers of epidermis (ex. athletes foot, ringworm)
- Caused by dermatophytes (uses keratin as carbon source/food)
- 3 different moulds, same MOP
- Clinical diseases are called “tineas”
15
Q
Systemic mycoses
A
- Infections in the deep tissues
- Caused by primary + opportunistic pathogens
- Most severe