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PRINCIPLES OF FUN > Introduction to fungi > Flashcards

Flashcards in Introduction to fungi Deck (42):
1

what is a fungus?

chemo-organic eukaryote that lacks chlorophyll and forms spores.

2

what does the cell wall of a fungus contain?

polysaccharides, often chitin or cellulose

3

what is the major sterol of the fungal membrane?

ergosterol

4

what is the mycelium?

the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae

5

what are the three groups of fungi?

basidiomycetes
ascomycetes
zygomycetes

6

what is the difference between the asexual spores of basidio and ascomycetes and zygomycetes?

zygomycetes asexual spore is sporangiospore as opposed to conidium

7

what is the structure of a basidiomycete?

basidiospores sit on top of the basidium, which is attached to the hypha

8

what is the structure of an ascomycete?

ascospores contained within a sac (ascus)

9

what is the structure of zygomycetes?

a rough walled zygote contains one or more zygospores

10

what are yeasts?

fungi that favour a unicellular habit

11

what diseases are caused by dermatophytes?

"ringworm" or TINEA:
capitis
facei
barbae
corporis
cruris
manum
pedis
unguium

12

when would conidiophore be released?

when nutrients are low and the fungi needs to try and sporulate (spread)

13

what are some causative agents of dermatophytosis (tinea)

epidermophyton microsporum and trichophyton spp

14

what is a causative agent of pityriasis versicolor?

malassezia spp., which are yeasts that also form hyphae in infected skin

15

when would a candida infection be fatal?

in immunocompromised patients where it can affect the deep organs.

16

what host factors can increase pathogenicity of fungal infections?

favourable (warm, moist) micro environments
broad spectrum antibacterial agents can reduce competition for epithelial colonisation sites in the gut
any immunosuppression

17

what different ways can a host become immunocompromised?

iatrogenic
disease processes
combinations of the above

18

what are some examples of iatrogenic immunosuppression?

steroid
anti cancer chemo
solid organ transplantation

19

what are some disease processes causing immunocompromisation?

AIDS
leukaemia
endocrinopathies

20

what are risk factors for candidiasis?

age, antibiotic therapy, endocrine disorders, immune defects, immune suppression, surgery

21

what is the most common type of candida species causing infection?

candida albicans

22

are candida yeasts?

Yes

23

can candida form hyphae?

Yes

24

what would cause a chronic mucocutaneous infection?

genetic defects
and endocrine defects and immune defects

25

what are the main causative species of aspergillosis?

aspergillus fumigatus

26

what diseases can aspergillosis cause?

asthma
aspergilloma
asthma ith eosinophilia

27

what type of fungus is apergillus?

mould

28

how does aspergillosis infection occur?

inhalation of conidia

29

what is a contributing factor to developing invasive pulmonary aspergillosis?

haematological malignancy

30

what is the main causative species of cryptococcosis?

cryptococcus neoformans

31

what diseases are caused by cryptococcus spp.

pulmonary cryptococcosis
meningitis (particularly in AIDS patients)

32

what are some diagnostic methods of detecting fungal infections?

histpathology
high-res CT scans
direct smear
detection of circulating fungal antigens
detection of circulating antibodies to fungi
PCR for fungal DNA
culture of fungus from normally sterile sites

33

how can dermatophytes be visualized?

directly in skin scales

34

what are some different classes of antifungal drugs?

triazoles and allylamines
echinocandins
polyenes
flucytosine

35

what do triazoles and allylamines target?

sterols

36

what do echinocandins target?

target cell wall

37

what do polyenes target?

target the fungal cell membrane

38

what does flucytosine target?

targets DNA synthesis

39

what are some examples of polyenes?

amphotericin B
Nyastatin

40

what are some examples of azoles?

clotrimazole
fluconazole
miconazole

41

what are some examples of echinocandins?

anidulafungin
caspofungin
micafungin (IV)

42

what are some problems with antigfungals?

spectrum of activity of the drug
IV vs oral
toxicity
resistance
cost
static or cidal