10 Flashcards
Diseases cause by fungi
Mycoses
SUPERFICIAL MYCOSES
Characteristics
Lacks immune response from host
• No living tissue invaded • asymptomatic
SUPERFICIAL MYCOSES
These are cosmetic fungal infections of the skin or hair shaft.
SUPERFICIAL MYCOSES Diseases
❏ Pityriasis versicolor
❏ Tinea nigra
❏ White piedra
❏ Black piedra
Also called Tinea versicolor
PITYRIASIS VERSICOLOR
PITYRIASIS VERSICOLOR Etiological agent
Malassezia furfur
A chronic, superficial fungal disease of the skin characterized by well-demarcated white, pink, fawn, or brownish scaly lesions.
PITYRIASIS VERSICOLOR
Basidiomycetous yeasts and form part of the normal skin flora
of humans and animals
Malassezia species
PITYRIASIS VERSICOLOR
o Laboratory diagnosis:
o Clinical Material o Skin scrapings
LABORATORY DIAGNOSIS culture of M. Furfur
Saboraud’s agar with olive oil or lanolin
o Stimulates growth by natural oils and other fatty substances
o Can grow on Sabouraud’s Dextrose Agar with cycloheximide and chloramphenicol (mycosel)
Specialized isolation medium containing glycerol-mono- oleate
Dixon Agar
Characterized by appearance, primarily on palms of the hand and occasionally the plantar and other surfaces of the skin as brown to black non scaly macules
TINEA NIGRA
TINEA NIGRA Etiologic agents
Hortaea werneckii
Hortaea werneckii example
Exophiala werneckii
Phaeoannellomyces werneckii
Cladosporium werneckii)
Clinical materials for the laboratory diagnosis of Tinea nigra
Skin scrappings
Direct microscopy of the laboratory diagnosis of Tinea Nigra
10% KOH (Potassium Hydroxide)
Direct Microscopy Examination (10%
KOH) of Tinea Nigra
- olive-brown, septate, multiple
branched hyphae and elongated budding cells - (+) ANNELIDE FORMATION
Culture for the laboratory diagnosis of Tinea Nigra
Saborauds dextrose agar
typical two-celled yeast cells producing annelloconidia (Tinea nigra)
LPCB mount:
Superficial infection of hair shaft
PIEDRA
PIEDRA 2 varieties
- white piedra - Trichosporon spp (asahi formerly beigelli)
- black Piedra - Piedraia hortae