Fungi

Question 1

Recognising fungi

Answer 1

Lectins e.g MBL which is a soluble PRR and can activate complement

Dectin1 recognises fungal glucan

Question 2

Polyenes e.g Amphotericin

Answer 2

Target ergosterol synthesis/membranes

Question 3

Azoles e.g Fluconazole

Answer 3

Target ergosterol synthesis/membranes

Question 4

Allylamines e.g Terbinafine

Answer 4

Target ergosterol synthesis/fungal microtubules

Question 5

Caspofungin

Answer 5

Targets beta-1,3-glucan synthesis

Question 6

Fungal toxins

Answer 6

Ergotamine toxin: vasoconstrictor

Mycotoxin: kills neutrophils

Question 7

Increased susceptibility to fungal infections

Answer 7

• Impaired IL-17; superficial infections
• Impaired neutrophils; deep filamentous mould
• Impaired T cells; yeasts, dimorphic fungi

Question 8

Histoplasma capsulatum

Answer 8

Dimorphic fungus; yeast at 37, filamentous mould at 24
Secretes CBP (ca2+ binding) to allow proliferation in macrophage vacuoles

Get lifelong persistent infection of macrophages controlled by Th1; granuloma

Systemic pathogen (I think)

Question 9

Candida albicans

Answer 9

Budding yeast
Forms toxin candidalysin at pseudohyphae which increases IL-1 and damages epithelial cells
Makes biofilm
Systemic opportunist; commensal on mucoid surfaces and only causes problems in compromised host

Treat with fluconazole

Question 10

Pneumocystitis (jiroveci)

Answer 10

Fission yeast
Sexual spore needed for transmission
Systemic opportunist
Obligate parasite
No ergosterol so target folic acid synthesis with trimethoprim/sufamethoxazole

Cause thickened alveolar walls

Question 11

Cryptococcus neoformans

Answer 11

Budding yeast
Environmental saprotroph in bird droppings
Get disease when T cells impaired

Can go via blood to the brain and cause progressive meaning-encephalitis and hydrocephalus

Question 12

Aspergillus

Answer 12

Opportunistic mould
Asexual spores

Can invade into blood of individuals with reduced neutrophils