MYCO & VIRULOGY L2 (Prelim- Subcutaneous & Cutaneous) Flashcards
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Infects outermost layer of skin or hair
Superficial mycoses
Causes patchy lesions/ scaling, dandruff, and prevalent during warm weather
Malassezia furfur
Appearance of an outer ring of a progressing infection
Malassezia furfur
Common sites of Malassezia furfur
- face
- chest
- trunk
- abdomen
Appearance of Malassezia furfur under KOH
- “spaghetti and meatballs fungus”
- budding yeasts
Positive for Malassezia furfur in wood lamp
Yellow fluorescence
Causative agent of “black piedra”
Piedraia hortae (Septate Dematiaceous)
Scalp hair infection, dark brown to black nodules that contain asci (saclike) structures and 8 ascospores
“black piedra” or Piedraia hortae (Septate Dematiaceous)
This is known as skin colonizer, warm loving, and usually found in tropical locations
Malassezia furfur
Also known as Tinea nigra
Hortaea werneckii
Also known as Tinea versicolor
Malassezia furfur
brown to black non scaly macules usually in palms and soles
Hortaea werneckii
Confused or misdiagnosed with malignant melanoma
Hortaea werneckii
Laboratory tests for Hortaea werneckii
- Skin scrapings
- 10-20% KOH
- Hyphal elements w/ budding cells
Trichosporon spp. is also known as?
“white piedra”
Occurs in hair shaft, opportunistic systemic pathogens, associated with immunocompromised diseases
Trichosporon spp.
A Trichosporon spp. that is known to be a human pathogen
Trichosporon beigelii
A Trichosporon spp. that is a systemic disease (meningitis)
T. mucoides
A Trichosporon spp. that is a fatal disease in immunocompromised hosts
T. asahii
Enumerate the important organisms that belong to Superficial mycoses
- Malassezia furfur - yeast
- Piedraia hortae
- Hortaea werneckii
- Trichosporon spp.- yeast
This term is used to describe organisms that are able degrade keratin
Dermatophytes (usually cutaneous mycoses)
This term is used to describe organisms that cannot degrade keratin
Non-dermatophytes (usually mga superficial mycoses)
Utilizes keratin as source of nitrogen
Dermatophytes (Cutaneous mycoses)
Important Genera that belonged to Cutaneous Mycoses
- Trichophyton - hair, skin, nails
- Microsporum - hair and skin
- Epidermophyton - skin and nails
Trichosporon spp. can be grown or cultured in?
Sabouraud Dextrose Agar (SDA)
Other tests that can be performed on Trichosporon spp. are?
- Carbohydrate fermentation
- Potassium nitrate
- Assimilation of sugars
- Urease Test
Most common cause of infection and is anthropophilic
Trichophyton
Caused by Trichophyton and appears as ringworm of the groin, or “jock itch”
Tinea cruris
Caused by Trichophyton and appears as ringworm of the beard
Tinea barbae
Caused by Trichophyton and appears as ringworm of the body
Tinea corporis
Caused by Trichophyton and appears as ringworm on the nail
Tinea unguium
Caused by Trichophyton and appears as ringworm of the feet, or “athlete’s foot”
Tinea pedis
Caused by Trichophyton and appears as ringworm of the scalp and hair
Tinea capitis
Laboratory diagnosis for Trichophyton
Direct Detection Methods such as stain
This stain reveals hyaline septate hyphae or arthroconidia
Calcofluor white or potassium hydroxide
Spores that fill hairshaft
Endothrix
Spores that ensheath hair shaft
Ectothrix
A clinically significant Trichophyton that causes crusty lesions made up of dead epithelia. Has antler hyphae and white and wrinkled colony
T. schoenleinii
Other term for T. schoenleinii
“Tinea favosa”
A clinically significant Trichophyton that is a nail dermatophyte, slow growing and its microconidia appears clavate- or peg-shaped
T. rubrum
IDENTIFY THE TRICHOPHYTON
Colony:
i. white, granular, & fluffy varieties
ii. yellow in younger colonies
T. mentagrophytes
A clinically significant Trichophyton that infects the nails. Its microconidia appear grapelike or teardrop-shaped
T. mentagrophytes
A clinically significant Trichophyton that is a hair dermatophyte and is larger than other dermatophytes.
Its colony appears white, tan to yellow, or rust, suede-like to powdery
T. tonsurans