Fungal classifications and yeast infections Flashcards Preview

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Flashcards in Fungal classifications and yeast infections Deck (49)
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1
Q

Why is fungal taxonomy so complicated?

A

Because many fungi can reproduce both sexually and asexually and the morphological characteristics of these stages are different.

2
Q

What are the 4 clinical classifications of fungi?

A

1 - Yeasts
2 - Molds
3 - Dimorphic fungi
4 - Poisonous mushrooms (homobasidiomycetes) –> mycetism

3
Q

How do yeast divide?

A

By binary fission

4
Q

Why is worrying about chronic infections due to molds nonsensical?

A

Spores of molds are everywhere, but people don’t just get sick off of them

5
Q

When would someone be likely to be infected or have bad outcomes with spores of molds?

A

When profoundly immunocompromised or if allergic to spores

6
Q

People that are capable of becoming allergic to a broad amount of allergens

A

Atopic

7
Q

What is the test to tell if someone is atopic?

A

A wool sweater is itchy on them

8
Q

What does dimorphic fungi mean?

A

Can grow as yeasts and as molds, depending on the culture

9
Q

Fungi that can produce higher toxins that can kill you, produce psychoactive effects, or make you very sick.

A

Homobasidiomycetes

10
Q

What is the meat of the homobasidiomycete mushroom made of?

A

Densely packed hyphae

11
Q

What is the scientific explanation for fairy rings (i.e. mushrooms growing in a perfect circle)?

A

Homobasidiomycete at the center, exsporulate in an explosive fashion on a night without wind. The spores will fall equidistantly from the center, and produce the fairy ring.

12
Q

Yeast ____ and divided, while molds form _______.

A

bud

hyphae

13
Q

Single, unconnected vegetative cells (fungi)

A

yeasts

14
Q

Grow similarly to bacteria, but are much larger.

A

Yeasts

15
Q

Fungi that reproduce by budding.

A

yeasts

16
Q

Fungi that do not sporulate.

A

yeasts

17
Q

Fungi used for commerical production of alcohol and citric acid and do not usually pose a hazard to laboratory workers.

A

yeasts

18
Q

How do molds grow?

A

Grow in a complex mass called a mycelium, composed of tubes called hyphae

19
Q

When hypha filaments are packed densely, the mycelium can appear to be a cohesive tissue. What fungal group has this?

A

Homobasidiomycetes

20
Q

How do molds reproduce?

A

form spores

21
Q

Aerial hypha

A

stolon

22
Q

Fruiting heads = ___________.

Stalk holding up the fruiting heads.

A

Sporangium/a

sporangiophore

23
Q

Describe how many spores are released from the mycelium.

A

Released in INCREDIBLE numbers

24
Q

How can spores become a contamination hazard?

A

Can become airborne and present a contamination hazard in labs working on pathogenic molds

25
Q

Spores are most commonly formed _________ (_________), but can also be produced _________ (_________)

A

asexually - conidia

sexually - ascospores

26
Q

What is the most common fungal infection (Causative agent)?

A

Candida albicans

27
Q

Most yeast infections are _________.

A

endogenous

28
Q

Most yeast infections are endogenous, except for ___________ ____________, which is associated with the excrete of gregarious birds, primarily pigeons?

A

Cryptococcus neoformans

29
Q

Cryptococcus neoformans is associated with what?

A

Excreta of gregarious birds

30
Q

What does gregarious bird mean?

A

Birds that flock together

31
Q

What are predisposing factors to superficial yeast infections?

A
1 - Wet work - e.g. dishwashers
2 - Pregnancy, oral contraceptives
3 - Diabetes mellitus
4 - Broad spectrym antibiotics
5 - HIV infection, CD4 < 500
6. Dectin-1 (Beta-glucan receptor) deficiency
32
Q

What does diabetes predispose you to?

A

Literally everything

33
Q

What are predisposing factors to deep yeast infections?

A
1 - Cytotoxic chemotherapy, corticosteroids
2 - Indwelling venous catheters
3 - Broad spectrum antibiotics
4 - Intravenous drug abuse
5 - HIV infection, CD4 < 200
34
Q

Why can safe injection sites be a meme?

A

because the drugs are not supervised

35
Q

Most common yeast causing infection.

A

Candida albicans

36
Q

Candida albicans is part of the normal flora where?

A

oropharynx, vagina, bowel and skin

37
Q

What does Candida albicans cause?

A

acute and chronic superficial infections of:
the skin - diaper rash, balanitis, intertriginous areas
nails - paronychia
mucous membranes - thrush, vaginitis
UTI

38
Q

Candida albicans can cause severe disease in who? What are they?

A

Immuncompromised patients
Esophagitis
pyelonephritis
sepsis

39
Q

What is balanitis?

A

superficial infection of the glans of the penis

40
Q

What are intertriginous areas?

A

skin on skin

41
Q

How would one describe a C. albicans rash?

A

Contiguous, red inflammed mass with silvery whiteish sheen

the defining feature are the satellite lesions

42
Q

What does thrush look like?

A

adherent white plaques with erythematous base

43
Q

What kind of odour may you smell with thrush?

A

freshly baked bread

44
Q

What is the major virulence factor of C. neoformans?

A

Capsule

45
Q

What is used to screen CSF samples for C. neoformans?

A

India ink test - stands out in darkfield microscopy

also latex agglutination test for antigens (positive)

46
Q

What can C. neoformans cause?

A

Diffuse pulmonary infection (usually asymptomatic)/progressive pulmonary disease with abscesses
or disseminated disease

47
Q

What are the risk factors for disseminated disease?

A

HIV, malignancy, corticosteroids

48
Q

What can C. neoformans cause, but very rarely?

What can we use to get rid of it?

A

Intracerebral mass lesions (cryptococcomata)

oral fluconazole

49
Q

C. neoformans can cause chronic meningitis in AIDS patients, but this meningitis is atypical. How?

A

will only have mild headache, but can walk around

unlike the usual coma which can occur with normal meningitis