mycology; dermatophytes Flashcards
what do dermatophyes do?
digest keratin and infect skill, hair, and nails
identifying features of microsporum canis
cottony white colony with a peripheral lemon-yellow margin
growth in 5-10 days
wood’s light +
cocoon-like macroconidia with square cells and tapered curved terminal ends
infect hair and skin in children
identifying features of microsporum gypseum
powdery cinnamon-brown colony with hairy extensions from the periphery
growth in 6-10 days
large, multi-celled conidia with rough walls and curved tips
microconidia are small, spherical, and produced laterally from hyphae
wood’s light neg
trychophyton mentagrophytes
growth in 5-10 days
smooth/silky powder on cornmeal agar
yellow to orange
thin hyaline and septate hyphae
rare macroconidia
microconidia are small spherical grape clusters along hyphae
urease + wood’s light -
causes inflammatory ringworm and penetrates hair shaft
Trichophyton rubrum
granular colony with radiating rugae and a red periphery
mature in 5-10 days
“birds on a fence” morphology
macroconidia are few or absent
microconidia are oval shaped and bilaterally attached to hyphae
causes tinea unguium
urease neg
Trichophyton tonsurans
urease +
yellow colony w/ shallow rugae and a suede like consistency
needs thiamine
7-10 days
birds on a fence, more oval microconidia
rare macroconidia
tear drop, balloon, or club shaped microconidia placed laterally from hyphae
Epidermophyton floccosum
silky-wooly grey colony
reverse is white
hyaline, thin and septate hyphae
macroconidia are conical, finger like in loose clusters
“bent-knee” effect
NEVER produce microconidia
causes traditional ring worm
Malassezia furfur
monomorphic yeast
lipophillic
2-4 days
spaghetti and meatballs morphology
causes tinea versicolor
Trichosporon Sp.
smooth yellow/white colonies w/ radial rugae
3-5 days to grow
arthroconidia have blastoconidia that mature and look like rabbit ears
cause piedra
