Intro To Fungi

Question 1

What are the 3 types of fungi?

Answer 1

Basidiomycetes (distinguished by presence of reproductive organ basidium.
E.g mushrooms

Ascomycetes (distinguished by ASCUS)
Eg yeast

Zygomycetes (distinguished by formation of zygospore within zygote during sexual reproduction)
E.g bread mouldy.

Question 2

What are mushrooms an example of?

Answer 2

BAsidiomycetes

Question 3

What is yeast an example of?

Answer 3

Ascomycetes

Question 4

What is mouldy bread an example of?

Answer 4

Zygomycetes.

Question 5

What are the different fungal infections? (5 types)

Answer 5

Dermatophytic - causative agents use keratin as a nutrient source.

Pityriasis versicolour - yeasts from in infected skin.

Candida - infect deep organs. MAin causative species = Candida albicans, candida tropicalis and candid glabrata.
Oral, vaginal , skin, nail, oesophageal, urinary tract. YEASTS.

Aspergillosis - asthma, aspergillosis (moulds) ubiquitous in environment. Occurs by inhalation of conidia. 
STrongly angioinvasive ( penetrate walls of blood vessels). 

Cryptococcosis - pulmonary cryptococcosis meningitis, particularly in AIDS patients.

Question 6

What is fungi?

Answer 6

Eukaryotic organisms that infect plants, insects, amphibians, mammals.
Can cause a range of diseases ON and IN humans.

Question 7

Host factors that contribute to pathogenicity of fungal infections

Answer 7

Warm, moist areas
Immunosuppressive of all types creates a window of opportunity for fungal invasion.
ANtibacterials - reduce competition.

Question 8

What is immunosuppressive?

Answer 8

Temporary stopping of immune system.

Question 9

Diagnostic methods for detecting fungi?

Answer 9

Direct detection = histiopathy, CT scans

Direct smear

Growth on selective medium

Detection of circulating fungal antigens

Detection of circulating antibodies

PCR (polymerase chain reaction) for fungal DNA

Culture of fungus from normally sterile site

Question 10

What are examples of anti-fungal drugs?

Answer 10

Triazole & allylamines - target sterols.

Echinocandins and is - target cell wall

Polyenes- target cell membrane

Flucytosine - target DNA synthesis

(Oral, IV)

Question 11

What are issues associated with anti fungal drugs?

Answer 11

Spectrum of activity
STATIC (stops growth but doesn’t kill)
Cidal(kills fungi)
Toxicity
Resistant
COST 
IV/oral issues.