Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micro final > Lect 24 > Flashcards

Lect 24 Flashcards

1
Q

What are Dermatophytes

A
  • pathogenic fungi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Dermatophytes require what for growth

A
  • keratin
    • hair, nails, skin
    • *do not infect mucosal surfaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Dermatophytes secrete what enzyme that allows for inhabiting keratinized regions of the body

A

keratinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three important genera of Dermatophytes? Which can form sexual spores?

A
  • Epidermophyton
  • Microsporum**
  • Trichophyton**
    • ** sexual spores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the infective stage of disease in Dermatophytes

A
  • Arthroconidium
    • can be visulaized in 1-% KOH wet mount
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are Dermatophytes diagnosed

A
  • Hyphae and Arthoconidia can be visualized in dead keratinized tissue
  • 10% KOH
  • dermatophyte test medium
  • sabouraud agar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the crude antigen of Dermatophytes (not seen on any other fungus)

A

Trichophytin: Galactomannan peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Trichophytin will create what two immune responses

A
  • CHO component: immediate response
  • peptide component: delayed response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

the dermatophyte test medium takes advantage of what property of dermatophytes

A
  • dermatophytes utilize nitrogenous compounds preferentially over carbohydrates
    • change pH (alkaline) - red color change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

dermatophytes can be classified into what 3 groups based on transmission

A
  1. Zoophilic
    • animal pathogens that may be transmitted to people
  2. Antrophophilic
    • human transmission
  3. Geophilic
    • transmitted through soil to people
  • usually invade non-viable keratinized tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What types of spores can dermatophytes produce

A
  • Arthrospores: person to person transmission; survive in environment
  • microconidia: asexual
  • macroconidia: asexual; usually multicellular
  • sexual spores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

typical clinical manifestation of dermatophyte infection

A
  • lesions are inflammed at edges with a central clearing zone
  • hair loss with itching, but not debilitating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

predisposing factors to developing dermatophyte infection

A
  • nail trauma
  • HIV
  • DM
  • immunosuppressive meds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an allergic dermal reaction to fungal antigens occuring in areas devoid of organisms

A

“Id reaction”: Dermatophytid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how to prevent dermatophyte infections

A
  • good personal hygiene
  • keep skin dry
  • regular housecleaning
  • use chlorine bleach and detergents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the most common Trichophyton species

A
  • T. tonsurans
  • T. rubrum
  • T. mentagrophytes
17
Q

features of Trichophyton species

A
  • all make pencil-shaped macroconidia with thin walls
  • not often fluorescent
  • produce
    • hyphae
    • microconidia
    • macroconidia
18
Q

What is the most common cause of tinea capitis

A

Microsporum canis

19
Q

features of Microsporum species

A
  • exhibit fluorescence under woods’s lamp
  • produce
    • hyphae
    • microconidia
    • macroconidia
      • large, spindle shaped
      • multicellular
      • thick walled
20
Q

Tinea capitis infects what

A
  • “ringworm of the scalp”
  • infects
    • endothrix: internal part of hair follcile
    • extothrix: external part of hair follicle
    • scalp
21
Q

In a tinea capitis infection, infected hair can break off leadint to

A

alopecia

  • see black dots of hair loss
22
Q

What does tinea pedis present as

A
  • athletes foot
  • itching, peeling and cracking of the skin
    • toe webs and soles
23
Q

Predisposing factors for Tinea corporis and Tinea cruris (jock itch)

A
  • Diabetes
  • obesity
  • excessive perspiration
24
Q

how is Tinea corporis and Tinea cruris (jock itch) transmitted

A
  • direct and indirect contact objects
    • towels, clothing, bed linen
25
Q

What is Tinea Unguium

A
  • onychomycosis: ringworm of the nail
26
Q

Tinea Unguium usually has co-infection with

A

candida species

27
Q

What is another name for Malassezia furfur

A

Tinea versicolor

28
Q

features of Malassezia furfur

A
  • short, unbranched hyphae and somewhat spherical cells
    • “spaghetti and meatballs” arrangement
  • yeast-like colonies
29
Q

Malassezia furfur has what growth factor that requires fat to grow

A
  • lipophilic growth factor
30
Q

clinical presentation

  • lesions occurs as a macular patch of depigmented or hyperpigmented skin that may enlarge, can lead to dandruff
A

Malassezia furfur

31
Q

how is Malassezia furfur diagnosed

A

microscopic exam in skin scrapings: KOH

32
Q

What is another name for Hortaea werneckii

A

tinea nigra

33
Q

unique features of Hortaea werneckii

A
  • dimorphic species
    • can grow as yeast or mold
  • can grow in saturated salt solutions
34
Q

Hortaea werneckii produces what that creates a brownish lesion

A

melanin

35
Q

how is Hortaea werneckii identified

A

KOH and microscopy

Micro final (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions