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Flashcards in Mycology Deck (19):
1

What are the main features of fungi?

-eukaryotic
-uni or multicellular
-mostly reproduce asexually (mitosis)
-monomorphic, dimorphic or polymorphic

2

What are the main components of fungi exteriors?

-rigid cell wall: chitin, glucans, mannoproteins

-cytoplasmic membrane: phospholipid bilayer w ergosterol

3

What are the 3 major classes of fungi?

-yeasts
-moulds
-dimorphic fungi (yeast and mould--> depends on temp, nutrietns, CO2)

4

What are the roles of aerial and vegetative hyphae in moulds (mycelium)?

aerial hyphae: support for reproductive structures

vegetative hyphae: provides nutrients to aerial hyphae

5

For dimorphic fungi, when are they seen in yeast form versus mould form?
(Hint: Temperature differential)

yeast form: in vivo or 37deg c.

mould form; 22-25 deg c.

6

List dimorphic fungi examples:

-Blastomyces dermatitidis *
-Histoplasma capsulatum *
-Sporothrix schenkii*
-Coccidioides immitis
-Paracoccidioides brasiliensis
-Penicillium marneffei

*endemic in Canada

7

What immune reactions are critical in eliminating fungi?

-nonspecific inflammatory reactions...esp neutrophil phagocytosis and killing.

8

Who is at increased risk of fungal infection that does not clear?

1. Patients with depressed neutrophil function/number:

-chemotherapy patients
-disorders of neutrophil funx: chronic granulomatous disease

2. Patients with depressed CMI (cell-mediated immunity):

-HIV

9

What are the 4 classifications of fungal infections (location):

1. mucocutaenous

2. superficial

3. subcutaneous

4. systemic

10

What is the most common mucocutaneous fungal infection?


What are the favourable conditions for these?

1. C. albicans

2. -moisture + warmth
-disruption of normal flora (ABs)
-diminished neutrophil phagocytosis and killing
-diminished cell-mediated immunity

11

What type of fungi typically cause superficial fungal infections?

Dermatophytoses

ex. Ringworm or Tinea (refers to serpentine lesion)

12

What do dermatophytoses use as nutrient source?

What enzyme do they use to do so?

-keratin

-keratinase

13

What are the 3 main epidemiological groups of superficial fungi?

1. Geophilic (soil) ex. Microsporum gypseum

2. Zoophilic (parasitic on animals) ex. Microsporum canis

3. Anthropophilic (humans) ex. Trichosporon rubrum

14

What are the 3 main genera of dermatophytes?

1. Trichophyton

2. Epidermophyton

3. Microsporum

15

Name a common superficial fungal infection:

What is it caused by?

-Tinea versicolor (Pityriasis versicolor)

caused by Malassezia furfur

16

What are the 2 common classes of subcutaneous mycetoma?

What population does it effect most often?

1. Chromoblastomycosis (caused by 'black moulds' in soil)

2. Mycetoma (caused by black moulds and fungus-like bacteria)

-effects barefooted populations in Tropics

17

List systemic fungal infections:

-Blastomyces dermatitidis (Blastomycosis)- Ontario + Manitoba
-Coccidioides immitis (Coccidioidomycosis)
-Histoplasma capsulatum (Histoplasmosis)
-Paracoccidioides brasiliensis (Paracoccidioimycosis)

18

List the characteristics of dimorphic fungi:

-geographically restricted
-produce asymptomatic to severe life threatening disseminated disease
- primary lung infx +/- dissemination
-soil organisms
-infect normal and immunocompromised hosts

19

List 3 opportunistic mycoses:

1. Candida albicans (Candidiasis)

2. Cryptococcus neoformans (Cryptococcosis)

3. Aspergillus species (Aspergillosis)