5. Superficial Mycoses Flashcards

1
Q

Superficial mycoses of the skin

A

Tineas

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2
Q

Superficial mycoses of the hair

A

Piedras

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3
Q

Media that specimens for superficial mycoses are inoculated to

A

SDA

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4
Q

Causative agent of Tinea versicolor

A

Malassezia furfur

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5
Q

Superficial infection of the keratinized layers of the skin

A

Tinea versicolor

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6
Q

Specimen for direct examination for tinea versicolor

A

Skin

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7
Q

Direct examination:

KOH will show yeastlike and hyphal forms

A

M. furfur

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8
Q

Lipophilic organism

A

M. furfur

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9
Q

Special culture method for M. furfur

A

Since it is lipophilic, add an oil overlay to the SDA and incubate at 37°C

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10
Q

Microscopic:

Thick-walled hyphae
“Yeast”, some budding

A

M. furfur

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11
Q

Microscopic:

Spaghetti and meatballs

A

M. furfur

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12
Q

Causative agent of Tinea nigra

A

Hortaea werneckii

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13
Q

Infection of the keratinized skin layers of the hand

A

Tinea nigra

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14
Q

How many days will H. werneckii mature?

A

21 days (slow grower)

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15
Q

Microscopic:

  • Septate, thick-walled hyphae
  • Yeastlike conidia
  • Chlamydospores
  • Annellides present (intercalary and lateral)
A

H. werneckii

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16
Q

Microscopic:

Initially has hyaline hyphae that become olive-colored

A

H. werneckii

17
Q

Infection of hair of beard and mustache

A

White piedra

18
Q

Causes white piedra

A

Trichosporon beigelii

19
Q

Appearance on SDA: yeastlike colonies

A

T. beigelii

20
Q

Micrscopic: nodule surrounding hair

A

T. beigelii

21
Q

Macroscopic:

Rapid grower
Yeastlike
Urease production

A

T. beigelii

22
Q

Microscopic:

  • many pseudohyphae and hyphae
  • blastoconidia (unicellular, variable in shape)
  • arthroconidia
A

T. beigelii

23
Q

Fungal infection of scalp hair

A

Black piedra

24
Q

Fungi acquired through swimming in rivers and stagnant waters

A

Piedraia hortae

25
Q

Causative agent of black piedra

A

Piedraia hortae

26
Q

Mycosis that forms black, stony, hard nodules on hair

A

Black piedra caused by Piedraia hortae

27
Q

Optimum growth temperature of Piedraia hortae

A

25°C (slow grower)

28
Q

Macroscopic:

  • Slow growing
  • small, folded, dark brown to black
  • may produce a reddish-brown diffusible pigment
A

Piedraia hortae

29
Q

Microscopic:

  • Septate, pigmented hyphae
  • asci containing 2-8 hyaline banana-shaped ascospores (ellipsoid, solitary, or in clusters)
A

Piedraia hortae

30
Q

Superficial mycoses infect the _____, _____, and _____.

A

Hair
Skin
Nails