BIGGY AGAR
CAT Nº: 1006
For the isolation and presumptive identification of Candida species
FORMULA IN g/l
Dextrose
10.00
Sodium Sulfite
3.00
Glycine
10.00
Yeast Extract
1.00
Bismuth Ammonium Citrate
5.00
Bacteriological Agar
16.00
Final pH 6.8 ± 0.2 at 25ºC
Candida albicans
PREPARATION
ATCC 10231
Suspend 45 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation.
Boil for one minute until complete dissolution. AVOID OVERHEATING. DO NOT AUTOCLAVE. Cool to 45-50ºC, mix well
and dispense into plates. The prepared medium should be stored at 8-15°C. The color is white-opaque.
The dehydrated medium should be homogeneous, free-flowing and beige in color. If there are any physical changes,
discard the medium.
USES
BIGGY AGAR is the abbreviation for Bismuth Glucose Glycine Yeast Agar. It is used to isolate and differentiate Candida
albicans and Candida tropicalis, and to differentiate the species according to the Nickerson method. Nickerson
discovered that Candida albicans can be differentiated from other Candida spp. on this medium based on colony
morphology.
Yeast extract is a source of vitamins, particularly of the B-group essential for growth. Glycine stimulates growth.
Dextrose is the fermentable carbohydrate providing carbon and energy. Candida spp reduce bismuth sulfite to bismuth
sulfide forming brown to black colonies. Bismuth ammonium citrate and Sodium sulfite inhibit bacterial growth without
affecting the growth of Candida species.
Inoculate and incubate at 25 ± 2°C for 18 - 72 hours, and up to 5 days if required. Freshly poured plates should
only be used. Inoculation onto slanted surfaces is not generally satisfactory.
The different species of Candida produce different kinds of infections. Candidiasis, the most commonly encountered
opportunistic fungal infection, is mostly caused by Candida albicans. Candida tropicalis and Candida glabrata infections
occur less often. Candida spp are present in clinical specimens resulting from environmental contamination, colonization,
or a disease process.
CHARACTERISTICS OF THE COLONIES
Differentiation is based on colony morphology.
1
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C. albicans: Brown to black, smooth,
circular or hemispherical colonies with a
slight mycelial fringe.
C. krusei: Large, flat, wrinkled colonies
with silvery black-brown grading into a
brown periphery and yellow halo.
C.
tropicalis: Dark brown, discrete
colonies, with black center prominence
and a slight mycelial fringe. Diffuse
blackening of medium, with this species
only, after about 72 hours of incubation.
C. parakrusei: Flat, frequently wrinkled,
C.
C. stellatoidea: Very dark brown, flat
pseudotropicalis: Dark reddishbrown,glistening, large, flat colonies with a
slight mycelial fringe.
medium-sized colonies, glistening dark
reddish-brown grading to light reddishbrown and an extensive yellowish mycelial
fringe.
medium-sized colonies
mycelial development.
with
almost
no
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures after incubation at a
temperature of 25 ± 2°C and observed after 18 – 72 hours, and up to 5 days if required.
Microorganisms
Candida albicans ATCC 10231
Growth
Colony Color
Good
Brown-to-black
Good
Brown-to-red
Escherichia coli ATCC 25922
Inhibited
-
Staphylococcus aureus ATCC 25923
Inhibited
-
Candida pseudotropicalis ATCC 14245
BIBLIOGRAPHY
Nickerson, W.J. 1953. Reduction of inorganic substances by yeasts. I. Extracellular reduction of sulfite by species of Candida. J. Infect.
Dis. 93:43.
Warren, N.G., and K.C. Hazen. 1955 Candida, Cryptococcus and other yeasts of medical importance, p. 723-737.
IN P.R. Murray, E.J. Baron, M.A. Pfaller, F.C. Tenover and R.H. Yolken (ed.)., Manual of clinical microbiology, 6th ed. American Society
for Microbiology, Washington D.C.
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com