dermatophytes Flashcards

1
Q

the cause of tinea or ringworm infections

A

dermatophytes

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2
Q

common characteristics of dermatophytes

A

all have septate hyphae- slow growers
often seen in KOH prep
ID by type of conidia they have
found on supporting structures known as conidiophores

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3
Q

microsporum

A

infect hair and skin
IF macroconidia- thick walled

macro and micro

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4
Q

trichophyton

A

infect hair, skin, and nails
if there are macro conidia they are thin walled

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5
Q

epidermopyton

A

infect skin and nails
macroconidia- club shaped; rare

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6
Q

dermatophytes can cause the hair to have

A

endothrix or ecothrix

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7
Q

ecothrix

A

usually doesn’t invade into the hair shaft

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8
Q

endothrix

A

means that is normally will invade into the hair shaft itself

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9
Q

what are dermatophytes best plated on

A

cornmeal or potato dextrose

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10
Q

gold standard for viewing conidial structure

A

slide cultures

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11
Q

microsporum audouinii

A

more common in kids
infect scalp, sometimes skin
microscop- juse see sterile hyphae (no spores); a few chlamydospores

comb like pectinate hyphae

wood lamps+

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12
Q

microsporum audouinii color

A

greyish white in color

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13
Q

Microsporum canis

A

transmitted puppies or kittens

scalp or skin infections

fluffy, yellow pigmented
reverse yellow

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14
Q

Microsporum canis ID

A

by macroconidia- have 6 septations and pointed ends

remember all dermatophytes have septate hyphae

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15
Q

microsporum gypseum

A

adults
geophilic organism and transmitted by infected dirt

skin infections

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16
Q

how is gypsum differentiated from canis

A

gypseum is more rounded at the end
-6 or less septations and described as cigar shaped

17
Q

Trichophyton mentagrophytes

A

very common in lab
transmitted: animals, dirt of humans

common cause of athletes foot and infection of nails

18
Q

Trichophyton mentagrophytes
hair infection type

A

endothrix- infect shaft

can see in hair penetration test

urea + in 4 days

19
Q

characteristics of Trichophyton mentagrophytes

A

microconidia looks like cross
characteristics coiling!!

20
Q

how is Trichophyton mentagrophytes
different from canis

A

mentagrophytes
-top is tan or buff colored and reverse is salmon

21
Q

most common infecting human

A

T.Rubrum

-mainly affecting skin and nails

22
Q

T.Rubrum

A

another common cause of athletes foot

elliptical or tear drop shape
micro- resemble “birds on a wire”

23
Q

T.Rubrum color

A

whitish and reverse is red
-enhance on corn meal

24
Q

major cause of tinea capitis

A

T.tonsurans

25
Q

disease that T.tonsurans causes

A

black dot ringworm
-hair will break off at shaft of scalp leaving black dot

26
Q

T.tonsurans microscopically

A

bizarre shaped microcon
may see club shaped or balloon
may see chlamydospores

27
Q

most severe form of tinea capitis

A

T.schoenleneii

28
Q

T.schoenleneii infection

A

may result in permanent hair loss and scarring of scalp

called favus

29
Q

T.schoenleneii microscopically

A

produce irregular hyphae said to look like favic chandeliars

-moose antlers

no macro or micro conidia

30
Q

common cause of jock itch

A

Epidermophyton floccosum

31
Q

Epidermophyton floccosum
ID

A

club shaped macro conidia in clusters of 2 or 3 at the end of hypael element

looks different for each cultures