Mycology Flashcards
What is the eukaryotic cell wall made of?
Chitin
What phyla has ribbon like non-septate hyphae?
Zygomycota
Deuteromycota (fungi imperfecti)
Asexual reproduction by Conidia
4 phyla
Zygomycetes
Ascomycetes
Basidiomycetes
Fungi Imperfecti (Deuteromycetes)
What agar should be used for hair, skin, and nail scrapings?
Mycosel agar - contains antibacterial and antifungal, KOH helps break down tissue for dermatophytes
Media for dimorphic fungi and dermatophytes?
Sabouraud dextrose agar (SDA)
Media that inhibits bacteria (for initial isolation except dermatophytes)
Inhibitory mold agar (IMA)
2 types of blood culture media
Inhibitory mold agar - inhibits bacteria and isolates fungi
Brain-heart infusion agar
BHI + gentamicin + chloramphenicol + sheep’s blood
C. neoformans from contaminated specimens
What is Niger (bird) seed agar for?
Isolation of C. neoformans - brown colonies due to melanin production
Also for C. Albicans (yeast cells only) and C. Dubliniensis (extensive pseudo-hyphal growth)
What is cornmeal agar (CMA) for?
Wide range of fungi but mainly fungi imperfecti
What is malt extract agar for? (MEA)
Zygomycetes
What is yeast extract phosphate medium for? (YEP)
Blastomyces dermatitidis and histoplasma capsulatum
What is dermatophyte test medium (DTM) for?
Dermatophyte recovery from contaminated specimens, media turns pink —> red for dermatophytes
Rhizopus vs. Mucor?
(Part of Mucorales)
Rhizopus: brown rhizoids at base of sporangiophore, umbrella structure at end of conidiophore (most common Mucorale), sporangia/sponrangiospores not retained
Mucor: no rhizoids, sporangia/sporangiospore stays intact
Dermatophytes
- hair, skin, nail infections
- break down and utilize keratin
Trichophyton, Microsporum, Epidermophyton
(remember two -phyton and one sporum)
Cutaneous mycoses (disease) in ringworm/Taenia
Tinea capitis: scalp hair loss
- Ectothrix: outside the shaft, permanent hair loss
- Endothrix: inside the shaft, temporary hair loss
- Favus: thick yellow crust, caused by T. schoenleinii
- Tinea barbae: beard hair loss, from animals
Ringworm infections
- Tinea corporis: body
- Tinea cruris: groin
- Tinea pedis/manuum: food/hand “Athletes foot”
- Tinea unguium: nails - discoloration
Trichophyton (Ascomcetes Phylum)
Part of Dermatophytes
Infected hairs do not fluoresce under Wood’s Lamp (UV)
Macroconidia - club shaped, rare, thin walled, smooth
Microconidia - numerous, spherical, pyriform (teardrop) or clavate (clublike)
Trichophyton rubrum
Does not perforate hair (ectothrix)
Slow growing
Urease (-)
Cherry red reverse surface
Microconidia - slender, clavate (clublike), tear shaped, birds on wire
Macroconidia: cigar shaped, rare
Trichophyton mentagrophytes
Perforates hair (extothrix)
Rapid growing
Urease (+)
Orange-red reverse surface
Coiled spiral hyphae
Microconidia - grape-like clusters
Macroconidia - cigar shaped
Trichophyton tonsurans
Epidemic form of tinea capitis (US)
Slow grower
Endothrix
Buff to brown, wrinkled, suede like
Reverse - yellow/reddish brown
Microconidia - flat base “matchstick”
Microsporum audouinii
(Dermatophytes)
Antler and raquet hyphae
Tinea capitis in children
Anthropophilic (attracted to humans as a source)
Ectothrix
Hair shafts fluoresce yellow-green
Cotton-y, salmon pink to reddish brown culture
Rice grain slopes (orange color on rice, not fluffy like M. canis)
Microsporum canis
(Dermatophytes)
Most common cause of ringworm in dogs and cats
Hair shafts fluoresce yellow-green under UV
Colonies: white, feathery border with yellow fringe
Reverse - bright yellow (or orange when aged)
Macroconidia: thick walled, spindle-shaped with curved ends, spiny projections on surface
Microsporum ferrugineum
(Dermatophytes)
*Endemic juvenile Tinea capitis in humans
Bamboo hyphae*
Epidermophyton floccusum
(Dermatophytes)
Skin and nail infection (not hair)
Anthropophilis
Colonies: brown yellow to olive gray or khaki, lumpy
Reverse - orange-brown, thin yellow border
No microconidia
Macroconidia: club shaped, rounded ends
Aspergillus fumigatus
- White to blue-green colonies
- Dichotomous branching of hyphae
- Conidial heads
Aspergillus niger
Peppery colonies
Dark pigmented spores
Penicillium
Blue-green colonies, velvety
Brushlike or broomlike conidiophores