Candida albicans produces pseudohyphae, regular clusters of blastoconidia along the points of septation, and large, spherical chlamydospores (Image H). Observing these features in a cornmeal agar preparation is helpful in identifying germ tube negative strains of C. albicans.
C. dubliniensis is similar in appearance to C. albicans on cornmeal agar. It has terminal chlamydospores that occur in pairs or clusters.
When grown on cornmeal agar, Geotrichum species are characterized by true hyphae that segment into rectangular arthroconidia. Arthrospores germinate from one corner, giving them a "hockey stick" appearance as indicated by the arrows in Image I.
Candida parapsilosis produces a crop of separated foci of growth that show radiating pseudohyphae and scattered blastoconidia, producing what are known as "spider" or "crossed matchstick" colonies (Image J).
Candida kefyr (pseudotropicalis) produces elongated blastoconidia that tend to line up along the pseudohyphae in a "logs in stream" arrangement (Image K).
Neither Cryptococcus neoformans nor Candida (Torulopsis) glabrata produce pseudohyphae. C neoformans are large, spherical, irregular in size and thick-walled, with spaces between cells, indicative of capsules (Image L). Candida (Torulopsis) glabrata are small, uniform in size, and more compactly arranged (Image M).
Rhodotorula rubra also does not produce pseudohyphae. It reproduces by successively budding, producing multilateral, oval yeast cells that may form short chains. It is usually pink to coral in color on cornmeal agar.
Saccharomyces are oval to round yeast cells with multilateral budding. Ascospores may be seen when ascospore or Kinyoun stain is used.
Trichosporon produce both hyphae and pseudohyphae. Blastoconidia are present. In older cultures, arthroconidia may also be present.
