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16 Cards in this Set
- Front
- Back
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Fungi
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Eukaryotic (nucleus, nuclear membrane, mitochondria), cell walls contain chitin (not cellulose), lack chlorophyll.
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Yeast
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Single vegetative cell, smooth colonies, reproduction by budding (blastoconidium). Appear like Staph colonies on blood agar.
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Moulds
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Produce mycelia (hyphae), fuzzy/hairlike colonies, sexual/asexual reproduction
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Direct exam of fungi
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KOH and calcofluor white
-Calcofluor is a fluorescent dye that binds chitin (shows fungal cell walls) India Ink -CSF to show capsules surrounding C. neoformans Gram stains -Used for yeasts (stain blue) and C. neoformans -Hyphae do not stain well |
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Media for fungi
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SDA: Sabourand Dextrose Agar
Chromagar/Cornmeal agar for Candida species Birdseed agar for C. neoformans Incubated at 30'C, days-weeks, moist environment |
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Mould identification
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Describe front and reverse of colonies. Identification based on pigmentation.
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Germ tube
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Examine for true hyphae. Does not constrict at point of origin like pseudohyphae. Incubate yeast w/ serum at 37'C for 2 hrs to look for germ tube production.
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Candida albicans
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Yeast. Positive germ tube (2.5hrs), Green on CAC (24-48hrs), Chlamydocondia (48hrs).
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Cryptococcus neoformans
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Mucoid colony, capsule on India ink, melanin production on birdseed agar. Urease positive.
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Dermatophyte
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Fungi that cause infections of skin, hair and nails. Skin infections termed Tinea.
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Dimorphic fungi
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Grow as mold (SDA) when incubated at RT (25-30'C).
Grows as yeast (on media w/ blood) at 35-37'C. D/t inhalation of conidia. |
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Coccidioides immitis
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Domorphic fungi. San Joaquin Valley (valley fever). Glistening, young, ice rink colony becomes cottony/fluffy in a week at 37'C.
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Opportunistic fungi
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Common in environment (usually not harmful to humans). Form w/in several days.
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Aspergillus fumigatus
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Inhalation of conidia. Morphology: large conidial heads (Richard Simmons).
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Trichophytan rubrum
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-toe nail fungus
-2 colony types b/t 7-10 days on SABHI at RT -red on reverse side -"birds on a wire" |
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Histoplasma capsulatum
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Dimorphic fungi. Mold phase show conidia at 90 degree angles to hyphae. Macroconidia are large w/ finlike edges.
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