Yeasts


Candida Species: Direct Examination


Candida Species


Candida albicans


FIG. 1. Candida albicans in the cerebrospinal fluid of a patient with a malfunctioning ventriculoperitoneal shunt.

candida albicans
candida albicans

FIG. 2. Candida albicans incubated in rabbit serum at 37° (germ tube test). Germ tubes are indicated by arrows and are the beginnings of true hyphae: no constriction is at the origin of the germ tube and the parent cell.

FIG. 3. Candida albicans on blood agar; moist, opaque colonies are characteristic of yeast.

candida albicans
candida albicans

FIG. 4. Candida albicans on a Dalmau plate. Clusters of round blastoconidia are present at some septae; thick-walled terminal chlamydospores (characteristic of C. albicans) are not seen in this image.


Candida tropicalis


candida tropicalis

FIG. 1. Candida tropicalis on a Dalmau plate.


Candida parapsilosis


candida parapsilosis

FIG. 1. Low power appearance of Candida parapsilosis on Dalmau plate. Note the characteristic "shaggy star" morphology.


Cryptococcus Species


Cryptococcus Species: Direct Examination


cryptococcus neoformans

FIG. 1. Cryptococcus neoformans in a bronchoalveolar lavage specimen; wright stain.

FIG. 2. Cryptococcus neoformans in blood culture; gram stain.

cryptococcus neoformans
cryptococcus neoformans

FIG. 3. Cryptococcus neoformans in sputum; wright stain.

FIG. 4. Cryptococcus neoformans in lung; H&E stain, low-medium power.

cryptococcus neoformans
cryptococcus neoformans

FIG. 5. Cryptococcus neoformans in lung; mucicarmine stain helps identify organisms.

FIG. 6. Cryptococcus neoformans in lung; GMS stain is a good, general-purpose fungal stain on tissue sections. The tiny black dots seen in this image are yeast within alveoli, seen at low power.

cryptococcus neoformans

Cryptococcus neoformans


Cryptococcus laurentii


cryptococcus laurentii

FIG. 1. Cryptococcus laurentii on Dalmau plate. Note the absence of hyphae.


Geotrichum species: yeast-like organisms

geotrichum
geotrichum

FIG. 1. Geotrichum in slide culture. Arthroconidia and hypha are seen here.


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Copyright © 2001, William McDonald, M.D.
Revised: 5 September 2002