intro to fungi + fungal diseases

Question 1

what is a fungus?

Answer 1

A chemo-organotrophic eukaryote that lacks chlorophyll and forms spores. Its cell wall contains polysaccharides, often chitin or glucan, and it absorbs nutrients. Its membrane contains ergosterol as the major sterol.

Question 2

what are the three groups of fungi?

Answer 2

• basidiomycetes
• ascomycetes
• zygomycetes

Question 3

what are yeasts?

Answer 3

fungi that favour a unicellular habit

Question 4

which fungi cause athlete’s foot?

Answer 4

Epidermophyton, Microsporum and Trichophyton spp.

Question 5

which fungus causes thrush?

Answer 5

Candida spp.

Question 6

what are the causative agents of dermatophytosis?

Answer 6

Epidermophyton, Microsporum and Trichophyton spp. - moulds with a predilection to degrade keratin as a nutrient source

Question 7

what are the causative agents of pityriasis versicolor?

Answer 7

Malassezia spp. - yeasts that also form hyphae in infected skin

Question 8

which host factors contribute to the pathogenicity of fungal infections?

Answer 8

• favourable microenvironment (warm, moist)
• broad-spectrum antibacterial agents reduce competition for epithelial colonization sites in the gut
• immunosuppression

Question 9

aspergillosis (as a result of aspergillis) causes what commonly?

Answer 9

simple asthma

Question 10

Cryptococcus are yeasts with a capsule and can cause…

Answer 10

pulmonary cryptococcosis, meningitis

Question 11

some examples of antifungal agents

Answer 11

amphotericin B, nystatin, clotrimazole, caspofungin