Yeasts Flashcards
Blastomyces spp.
8 to 15 um diameter round, deeply basophilic spores with a ~1 um clear, biconcave cell wall around a deeply basophlic, slightly granular center. Spores exhibit broad based budding.
Histoplasma spp.
2-4 um oval to piriform eosinophilic spores with a thin, clear cell wall around an eccentrically placed crescent shaped nucleus (giving a 1/2 full appearance).
Crytptococcus spp
spherical yeast organisms 8-40 um in diameter and composed of a 4-15 um diameter round lightly basophilic, granular center surrounded by a variably thick, clear, non-staining capsule (12-20 um). Spores exhibit narrow-based budding. Rough forms lack capsule.
Sporothrix
3-9 um long x 2-3 um wide fusiform to cigar shaped, with a 0.5 um clear/nonstaining capsule, containing medium blue cytoplasm, and a slightly eccentric amphophilic, ovoid nucleus. Display narrow based budding
Coccidioides
Spherules are large, 10-200 um, round, blue spheres with a clear 1-2 um cell wall surrounding a lightly basophilic, finely granular area with a folded/ crumpled appearance. Endospheres are 2-5 um round to ovoid, light blue structures with a thin clear cell wall and dark blue, eccentric nuclei.
Malassezia
4-6 um smooth, deeply basophilic, bilobed oval to peanut shaped yeast spores. Gram +
Candida
2-3um x 4-5 um, smooth ovoid, deeply basophilic budding yeast cells; hyphae and pseudohyphae are 2 um in diameter and vary in length. These stain medium to dark blue and are surrounded by a thin, clear halo/ wall (~0.25-0.5 um)
Cyniclomyces gluttalus
oblong cylindrical to branching structures approx 5 um wide and varying from 10-20+ um in length. Mottled blue internal staining with a central, deeply basophlic transverse band outlined by1-2 thinner, paracentral clear areas that sometimes contain eosinophilic granular material.
Dermatophytes (Trichophyton, Microsporum)
medium to dark blue mycelia and spores SIZE???. thin, clear cell wall. Stain with GMS or PAS to highlight spores
