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
Paecilomyces/Purpureocillium lilacinum
Pink fuzzy
Looks similar to penicillium but pointier and oblong spores
Fusarium
Canoe shaped macroconidia
Pink on media
Contact lens wearers
100% mortality in BM transplant infections
Blastomyces dermatitidis
Broad base, lollipop like
Sexual stage - Ajellomyces dermatitidis
Lungs —> disseminates
Coccidoides immitis
Valley Fever
Inhalation of arthrospores from soil or dust
Ice rink colonies
*Barrel-shaped arthroconidia
Spherules*
Histoplasma capsulatum
Cave disease/Darling disease
*Birds and bats
Tuberculate macroconidia*
Sepedonium
Looks like histoplasma but noninfectious
Sporothrix schenckii
Rose Gardener’s Disease
Transmission: thorns
*Flowerets attached to conidiophore
Cigar bodies*
Paracoccidioides brasiliensis
South American blastocycosis
Chronic granulomatous disease
Mariner’s Wheel or Ship’s Wheel
Talaromyces (Penicillium) marneffei
Wine red pigment
Looks like penicillium
Hortaea werneckii
Tinea nigra - skin infection affecting palms of hands and soles on feet (black non-scaly macules)
Hyphal fragment and budding yeast
Piedraia hortae (black piedra)
Hair and scalp infection
Dark brown black nodules on hair
Nodules contain asci
White grain Mycetomas
Pseudallescheria boydii
Acremonium
Fusarium
Pseudallescheria boydii
Sexual stage
Asexual stage = Scedosporium boydii
Acremonium
Looks like a beehive (on an acre)
Black grain Mycetomas
Curvularia
Madurella mycetomatis
Exophiala jeanselmei
Curvularia
Looks like croissants (curved conidia)
Madurella
Causes most cases of black grain eumycotic mycetoma in Africa
Chromoblastomycosis
Copper bodies
Cladophialophora
Phialophora verrucosa
Fonsecaea pedrosoi
Rhinocladiella aquaspera
Cladophialophora
Attaches at 2 spots
Phialophora verrucosa
Vase shaped phialides with cup-like collarettes
Fonsecaea
Copper pennies
Looks like asterisks
Rhinocladiella aquaspera
Not branched, looks like longer stem than Cladosporium
Phaeohyphomycosis
*Infection caused by dematiceous fungi)
Alternia
Drugstick-like conidia
Bipolaris
*Zig zag
Peas in a pod*
Exseronilum rostratum
Fungal meningitis, looks similar to Bipolaris kind of
Pneumocystis jirovecii
Pneumocystis pneumonia (PCP)
HIV/AIDS
Cyst, trophozoite, sporozoites stages
Needs tissue culture to grow (can’t grow on regular fungal media)
Yeast that buds asexually
Blastoconidia
Candida albicans
True germ tube
Green on chromagar
Pseudohyphae
C. glabrata
Mauve colonies on CHROM
Rapid assimilation of Trechalose
Does not form pseudohyphae (feet) on colonies
funginemia in immunocompromised patients, fluconazole resistant
C. krusei
Urea (v)
Innate resistance to Fluconazole
Resistance to Amphotericin B
C. dubliniensis
Cannot grow at 42-45°C (differentiates from C. albicans)
C. auris
Serious global threat
Resistant to all 3 antifungals
Does not form pseudohyphae or germ tube
Can persist on surfaces and spread between patients
Cryptococcus neoformans
Polysaccharide capsule
Stain: India ink
C. neoformans and C. gattii produce phenoloxidase —> produces brown pigment on Niger Seed Agar
C. gattii vs. C. neoformans
C. gattii turns blue on CGB agar
C. gattii from Eucalyptus trees
Trichosporon
White piedra
Numerous anthroconidia - rectangular anthroconidia with round ends
Urease (+)
Malassezia furfur
Tinea versicolor - brown lesions on light skin people, light lesions on darker skin people
Malassezia pachydermatis
Fungemia in immunocompromised patients
Malessezia
*Spaghetti and meatballs hyphal arrangement
Bowling pin or pop bottle morphology
Budding yeast with collarettes*
Rhodotorula
Bright salmon pink color
Urease (+)
Capsulated
5-Fluorocytosine (Flucytosine)
DNA and Protein Synthesis Inhibitor
Fluconazole (part of Azole Agents) and Amphotericin B
Cell Membrane Inhibitor
C. krusei - resistant to fluconazole and Amphotericin B
Amphotericin B - binds esterol
Echinocandin (1, 3 beta-glucan synthase)
Glucan synthesis inhibitor
Sterile structures on which spore bearing Phialides are born in Penicillium
Metulae
Sexual phase of zygomycetes
Zygospores
