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Flashcards in Fungi Deck (63):
1

What is the unicellular growth form of fungi? how do they reproduce?

yeast- budding

2

What is it called when yeast cell buds do not separate

pseudohyphae

3

What are hyphae

threadlike branching, cylindrical tubules of fungal cells attached end by end

4

What are molds

mycelia
multicellular colonies of clumped hyphae
produce spores

5

what are dimorphic fungi

fungi that grow as either yeast or mold depending on environment and temperature

6

What are Saprophytes

fungi that live in and utilize organic matter as energy source

7

Describe the innermost layer of fungi

cell membrane that is bilayer and has lots of sterols- ergosterol

8

How do most antifungals work

disrupting ergosterol
like amphotericin B and nystatin
or ergosterol syntehsis- azoles

9

What component of fungi are strong Ag to human immune system

the Cell wall

10

What stain do you use to visualize the capsule of fungi

India ink stain

11

What are the superficial fungal infections

pityriasis versicolor and tinea nigra

12

what is presentation of pityriasis versicolor

hypo and hyper pigmented patches on the skin
caused by Malassezia furfur

13

What is the presentation of tinea nigra

causes dark brown black painless patches on soles of hands and feet
caused by exophiala werneckii

14

How do you Dx tinea nigra or pityriasis versicolor

skins crapings mied with KOH will reveal hyphae and spherical yeast

15

What is the best Tx for superficial fungal diseases

dandruff shampoo that has selenium sulfate

16

what fungi cause cutaneous fungal infections

dermatophytes

17

What enzyme do dermatophytes secrete

keratinase

18

What are the most common dermatophytes

Microsporum, Trichophyton and Epidermophyton

19

presentation of tinea corporis

ring with red raised border
areas of active inflammation and area of healing in middle
ring worm

20

What is tinea cruris

jock itch
itchy red patches on groin and scrotum

21

what is tinea pedis

athletes foot
cracking and peeling of skin between toes

22

what is tinea capitis

scaly red lesions with loss of hair on scalp

23

what is tinea unguium

thickened nails that are discolored and brittle
onychomycosis

24

What do you use to Dx microsporum

direct examination of hair and skin with Woods light
will fluoresce green

25

What does candida albicans cause

oral thrush, diaper rash and vaginitis

26

how do subcut fungal infections gain entrance

trauma to the skin

27

What causes sporptichosis

sporothrix schenckii

28

Presentation of sporothrichosis

subcut nodule that becomes necrotic and ulcerates
follows lymph tracts
yeast at 37 C
hyphae at 25C

29

What is quick cheap Tx for sporothrichosis

Potassium iodide

30

What is chromoblastomycosis? what cause it

subcut infection caused by variety of copper-colored soil saprophytes found on rotting wood
Phialophora and Cladosporium

31

Presentation of chromoblastomycosis

small violet wartlike lesion that over mo-yrs many arise nearby, look like cauliflower

32

How do you Dx chromoblastomycosis

KOH reveal copper-colored sclerotic bodies

33

What fungi cause systemic disease in humans

Histoplasma capsulatum, Blastomyces dermatidis, Coccidioides immitis

34

Describe characteristics of the fungi that cause systemic disease

dimorphic
mycelial forms with spores at 25 C
yeast form at 37 C

35

Where are Histoplasma and Bastomyces endemics

Mississippi River area

36

Where is Coccidioides endemic

Arizona and old southwestern areas

37

AIDS patient with opportunistic infection that previously lived in Arizona. most likley Dx?

Coccidioides

38

What are the 3 clinical presentations of the systemic fungi

asymptomatic
pneumonia- like TB
disseminated- rare

39

What is the best way to Dx systemic fungi

biopsy of affected tissue
silver stain
NOT PPD type because many people have been exposed

40

What is different of systemic fungal infections vs TB

not person to person transmission
fungi have spores, not acid fast

41

What is Histoplasma capsulatum assoc with

exposure to bat and bird droppings
cleaning chiken coops or spelunking

42

What is presentation of Blastomyces dermatitidis

weight loss, night sweats, lung involvement and skin ulcers

43

What type of fungi is Cryptococcus

polysaccharide encapsulated yeast, not dimorphic

44

What is the major manifestation of cryptococcus infection

meningoencephalitis

45

Where is cryptococcus neoformans found? what population does it infect?

pigeon poop
AIDS paitents- 10%

46

What is the risk of cryptococcal meningitis without Tx

death from cerebral edema and brainstem compression

47

What is the Dx for cryptococcus infection

lumbar puncture and CSF analysis

48

What does the India ink stain of cryptococcus look like

halo of polyscarrachride capsule around yeast cells

49

What is the most sensitive/confirmatory cryptococcal lab

cryptococcal Ag test

50

What are the 3 cutaneous infections caused by Candida

oral thrush- creamy white exudate
Vaginitis- cottage cheese
diaper rash- red and macerated

51

What can candida cause in immunocompromised host

esophagitis- burning substernal pain worse with swallowing
disseminated- every organ
see white fluffy candidal patches in retina

52

What is the clinical pearl of candida detection in samples

normal in urine, stool and sputum
abnormal in blood!!!! immunocompromised

53

What 3 types of diseases are caused by Aspergillus

Allergic Bronchopulmonary Aspergillosis (ABPA)
infection in preformed lung cavities "Aspergilloma"
invasive infection of lung "invasive aspergillosis"

54

What type of reaction is ABPA

type 1 HS reaction IgE mediated with bronchospasm
blood eosinphilia
also type 4 DTH with cell mediated inflammation and lung infiltrates

55

What is an aspergilloma

lung cavitations from TB or malignancies that grow aspergillus fungal ball in cavity

56

What is Tx for aspergilloma

surgical excision

57

What is presentation of invasive aspergillosus

slowly progressive asymptomatic pneumonia, multiple nodular infiltrates
high mortality rate

58

What toxin does aspergillus secrete? where is it most prominent?

Aflatoxin
peanuts grains and rice in sahara desert in Africa

59

What patients are at highest risk for mucormycosis infection

profound acidotic patients like diabetics, immunocompromised, burn patients or those taking iron chelator deferox-amine

60

What areas do the mucormycosis fungi infect

sinuses, cranial bones and blood vessels

61

What are the fungi like bacteria

Actinomycetes and Nocardia

62

What is important about Actinomycetes

gram + filamentous beaded anaerobe
normal flora
eroding abscesses
sulfur granules
treat with Penicillin

63

What is important about Nocardia

gram + beaded filamentous ACID FAST
not normal flora
misDx as TB alot
Tx with sulfamethoxazole