CANDIDA

SPECIES

Candida albicans
Candida guilliermondii
Candida kefyr
Candida krusei
Candida lipolytica
Candida lusitaniae
Candida parapsilosis
Candida stellatoidea
Candida tropicalis
Candida zeylanoides

MICROSCOPIC APPEARANCE

Hyphae are septate, hyaline. Conidiophores are short and inflated. Conidia are black with thick walls.

MACROSCOPIC APPEARANCE

Surface: Texture smooth; Cream to white colonies on surface.
Growth Rate: Rapid to very rapid growth.
Other: Some species may show a mycelial fringe.

DISTINGUISHING FEATURES

Candida produces blastoconidia singly or in small groups all along graceful, long pseudohyphae. True hyphae may also be present. A few teardrop-shaped chlamydospores may rarely be produced. Candida albicans , produces pseudohyphae, with clusters of round blastoconidia at the septa and large, thick-walled terminal chlamydospores.

HABITAT

Candida are cosmopolitan, commonly found as normal flora in the skin, mouth, vaginal mucous membranes, and stools. Also found on leaves, flowers, water and soil.

PATHOGENICITY

Cutaneous and opportunistic systemic mycoses. Candida albicans is the most common of candidiasis (candidosis), which is an acute, subacute, or chronic infection involving any part of the body. Other species vary from non-pathogenic to low virulence, causing disease in the immunocompromised patient.

Characteristics of Candida spp.
Most Commonly Encountered in the Clinical Laboratory
Organism Microscopic Morphology on
Corn Meal Agar with
Tween ® 80


at 25 o C.
Growth in Sabouraud Broth Growth with Cycloheximide at 25 o C. Growth on SDA at 37 o C. Germ
Tubes
Candida
albicans
Pseudohyphae with terminal chlamydospores; clusters of blastoconidia at septa No surface growth Positive Positive Positive
Candida
guilliermondii
Fairly short, fine pseudohyphae; clusters of the blastoconidia at septa No surface growth Positive Positive Negative
Candida
kefyr
Elongated blastoconidia resembling "logs in a stream" along pseudohyphae No surface growth Positive Positive Negative
Candida
krusei
Pseudohypae with
"cross-matchsticks" or "tree-like" blastoconidia
Wide surface film up sides of tubes Negative Positive Negative
Candida
lipolytica
Elongated blastoconidia in short chains along pseudohyphae Pellicle
(delayed)
N/A Positive with strain variation Negative
Candida
lusitaniae
Short chains of elongate blastoconidia along curved pseudohyphae No surface growth Negative Positive Negative
Candida
parapsilosis
Blastoconidia along curved pseudohyphae; giant mycelial cells No surface growth Negative Positive Negative
Candida
stellatoidea
Blastoconidia anywhere along pseudohyphae No surface growth Negative Positive Positive
Candida
tropicalis
Blastoconidia anywhere along pseudohyphae Narrow surface film with bubbles Negative with strain variation Positive Negative
Candida
zeylanoides
Pseudohyphae give "feather-like" appearance at low power Pellicle
(delayed)
Negative Negative with strain variation Negative

RECOMMENDED MEDIA

Incubate at 25 degrees C. for 3 days.

REFERENCES

1. Hensyl, William R., et al. 1990. Stedman's Medical Dictionary , 25th ed. Williams & Wilkins, Baltimore, MD.

2. St. Germain, Guy and Summerbell, Richard, Ph.D. 1996. Identifying Filamentous Fungi , 1st ed. Star Publishing Company, Belmont, CA.

3. Larone, Davise, H. 1995. Medically Important Fungi , A Guide to Identification . 3rd ed. American Society for Microbiology Press, Washington, D.C.

4. The Oxoid Vade-Mecum of Microbiology . 1993. Unipath Ltd., Basingstoke, UK.

5. Sutton, D.A., et al. 1998. Guide to Clinically Significant Fungi , 1st ed. Williams & Wilkins Publishing, Baltimore, MD.


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