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Principles of disease (Ross Lilley) > Introduction to Fungi > Flashcards

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1

classification of fungi

principally based on morphology. Three major types:
-Basidiomycetes (Mushrooms)
-Ascomycetes
-Zygomycetes (moulds)

2

Dermatophytosis

an infection of the skin caused by moulds with a predilection to degrade keratin as a nutrient source.

3

fungi that cause dermatophytosis (ringworm/tinea)

-epidermophyton (epidermophyton floccosum)
-microsporum (microsporum canis)
-trichophyton (trichophyton mentagrophytes)

4

pityriasis versicolor

caused by malassezia spp. causes discoloured blotches on skin.

5

what do Candida spp. infect?

infect deep organs of patients with various types of immune dysfunction.

6

which patients are susceptible to aspergillus spp. infections?

infect deep organs of patients undergoing treatments such as chemotherapy and stem cell transplantation

7

Candida infections (candidiasis, candidosis)

cause a wide range of infections:
oral
vaginal
skin
nail
oesophageal
urinary tract
disseminated

8

candida species

candida:
albicans
tropicalis
glabrata

9

what type of fungi is candida?

yeast

10

aspergillus infections (aspergillosis)

-simple asthma
-asthma with eosinophilia (high levels of eosinophils)
-aspergilloma
-invasive bronchopulmonary aspergillosis
-disseminating aspergillosis

11

aspergillosis causing spp.

-aspergillus fumigatus
-aspergillus flavus

12

what type of fungi are aspergillus spp. ?

moulds

13

cryptococcus infections

-pulmonary cryptococcosis
-meningitis
-disseminated infection

14

In what type of patients do disseminated infections occur?

seriously immunocompromised patients

15

main causative species for cryptococcosis

-cryptococcus neoformans
-cryptococcus gattii

16

describe the properties of fungi

chemo-organotropic eukaryote that lacks chlorophyll and forms spores.

17

host factors that contribute to pathogenicity of fungi

-favourable micro-environments encourage growth of fungi on skin and mucous membranes
-broad spectrum antibacterial agents reduce competition for epithelial colonization sires in gut
-immunosuppression of all types may create a window of opportunity for fungal invasion

18

diagnostic methods for identifying fungal infections

-direct detection (histopathology, high-res CT scans
-detection of circulating fungal antigens
-detection of circulating antibodies to fungi
-PCR for fungal DNA
-culture of fungi form normally sterile sites

19

mechanisms of action for antifungal drugs

target:
-cell walls (echinocandins)
-cell membrane (polyenes)
-target DNA synthese (flucytosine)
-target sterols (triazoles and allylamines)

20

issues with antifungal agents

toxicity- drugs may be toxic to patient
resistance- fungus may develop resistance to drug
cost- treatments can be expensive

21

echinocandins action

target cell wall

22

polyenes action

target cell membrane

23

flucytosine action

target dna synthesis

24

triazoles and allylamine action

target-sterols