Fungi Flashcards

1
Q

What are common fungal infection?

A

Cryptococcus neoformans
Candida infections - oral/vaginal/systemic
Aspergillus fumigatus
Superficial infection (dermatophyte/nail)

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2
Q

What are fungi? (function)

A

FUNCTION: chemo-organotrophic eukaryote that lacks chlorophyll and forms spores.

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3
Q

What are fungi (structure)?

A

STRUCTURE: cell wall contains polysaccharides, often chitin and cellulose and it absorbs nutrients. Its major membrane contains ergosterol as the major sterol.
Sterol = type of lipid, subgroup of steroids

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4
Q

Groupings of Candida species problem

A

Grouped by morphology NOT genetic relatedness

Why? For clinical identification

Problem: identifying to Genus is not enough, resistance varies greatly between

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5
Q

Fungal Kingdom (groups)

A

Basidiomycetes
Ascomycetes
Zygomycetes

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6
Q

Main, high mortality fungal infections of immunocompromised

A

Candida spp. Infect deep organs of patients with various types of immune dysfunction

Aspergillus spp. Infect deep organs of patients undergoing e.g. chemotherapy, stem cell transplantation

Crypotcoccus spp. - moves from lungs to nervous system

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7
Q

What is Aspergillus fumigatus?

A

Farmers’ lung

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8
Q

Of the larger groups, which one do Cryptococcus spp. belong to?

A

Basidiomycetes

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9
Q

Example of an Ascomycetes fungi

A

Candida spp., Aspergillus spp., Neurospora

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10
Q

Example of a Zygomycetes fungi

A

Rhizopus species, bread moulds

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11
Q

Cause of athlete’s foot

A

Epidermophyton

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12
Q

Cause of thrush

A

Candida spp.

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13
Q

Cause of a lot of skin conditions (inc. dandruff)

A

Malassezia spp.

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14
Q

Classes of antifungals

A

polyenes
azoles
echinocandins

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15
Q

What is a cause of dermatophyte infections?

A

tinea - use keratin as a food source

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16
Q

Outline Chronic mucocutaneous

candidiasis (CMC)

A
can arise in individuals with
an unusual combination of
endocrine and immune
dysfunction (autoimmune
polyendocrinopathycandidiasis
-ectodermal dystrophy —
APECED)
  • more vulnerable to fungal infections
17
Q

Main causative species of Candida infections

A
C. albicans
C. tropicalis
C. glabrata
C. krusei
C. parapsilosis
18
Q

What sort of infections do Candida spp. cause?

A

oral/vaginal/skin/nail/oesophageal/urinary/disseminated

19
Q

Main causative species of Aspergillus infections

A

A. fumigatus

A. flavus

20
Q

What sort of infections do Aspergillus spp. cause?

A
simple asthma
asthma with eosinophilia
aspergilloma
invasive - bronchopulmonary/aspergillosis
disseminated aspergillosis
21
Q

What is are aspergillus infections mainly associated with?

A

haematological

malignancies

22
Q

Main causative species of Cryptococcus spp. infections

A

Cryptococcus neoformans

C. gattii

23
Q

What sort of infections do Cryptococcus spp. cause?

A

pulmonary cryptococcosis
meningitis
disseminated infection

24
Q

Examples of Azoles

A

Fluconazole
Voriconazole
Posaconazole

25
How do Azoles work?
``` Target ergosterol (cell wall) Make ergosterol into a toxic sterol ```
26
Example of a Polyene
Amphotericin B
27
How do Polyenes work?
Target membrane Binds to ergosterol, makes pore in membrane
28
Example of an Echinocandin
Caspofungin
29
How do Echinocandins work?
Target cell wall Causes cell wall stress by blocking 1,3 beta glucan synthase
30
Types of Cryptococcus spp. that cause disease
Cryptococcus neoformans Cryptococcus gattii (complex of C. bacillisporus and C tetragattii)
31
What is special about Cryptococcus gattii?
Can target non-immunosuppressed people
32
Fungal pathogens in immunosuppressed - unattributed
Rhizopus arrihizus | Exophiala
33
Non-fatal fungal infection examples
Athlete's foot - Epidermophton, Microsporum and Trichophyton spp. Thrush - Candida spp. pityriasis versicolor - Malassezia spp. Dermatophyte infections - tinea (keratin feeding)
34
What is the significance of GXM and GXMGal?
Forms Capsule around Cryptococcus- major role in virulence
35
What is the significance of titan cells?
Higher virulence - found more in Cryptococcus gattii (tetragattii) - also protection when inside macrophage
36
Interesting feature of Cryptococcus when taken in by macrophage
vomocytosis | - makes the macrophage release it