BiGGY AGAR

Cat. no. G17 BiGGY Agar, 15x100mm Plate, 18ml 10 plates/bag
Cat. no. R21 BiGGY Agar, 13x100mm Tube, 3ml Slant 20 or 100 tubes/box

INTENDED USE

Hardy Diagnsotics BiGGY Agar (Bismuth Sulfite Glucose Glycine Yeast Agar) is a selective and differential medium used in the isolation and presumptive identification of Candida spp.

SUMMARY

BiGGY Agar was developed by Nickerson in 1953 following a study of sulfite reduction by Candida species. Nickerson found many yeast capable of reducing bismuth sulfite to bismuth sulfide when grown on an acidic or neutral medium containing the reducing substrate. Substrate reduction was noted by the production of brown to black pigmented colonies, a result of sulfide combining with bismuth. (1-7)

Bismuth sulfite inhibits bacterial growth, thereby enabling the recovery of isolated colonies of Candida . Candida spp. reduce the bismuth sulfite resulting in pasty brown to black colonies. Some Candida species present as brown to black colonies surrounded by zones of dark precipitate in the medium. Dextrose and yeast extract provide the nutrients in the formulation.

FORMULA

Ingredients per liter of deionized water:*

Dextrose 10.0gm
Glycine 10.0gm
Bismuth Ammonium Citrate 5.0gm
Sodium Sulfite 3.0gm
Yeast Extract 1.0gm
Agar 20.0gm

Final pH 6.8 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Storage: Upon receipt store at 2-8ºC. away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.

PRECAUTIONS

PROCEDURE

Specimen Collection: Infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport media and refrigerated until inoculation. Consult listed references for information on specimen collection. (1-5)

BiGGY Agar should be inoculated, incubated, and results recorded according to accepted procedures described in the listed reference texts. (1-5)

The streak plate technique is used primarily to obtain isolated colonies from specimens containing mixed flora. When inoculating slants, streak the surface with a sterile inoculating loop using two to three isolated colonies.

BiGGY Agar may be used directly for isolation and growth as well as for the presumptive recognition of Candida spp.

When used as a direct medium, BiGGY Agar should be inoculated as for routine bacterial isolation and incubated at 25-30ºC. The medium should be examined daily for a period of up to 5 days.

When used as a secondary test medium, an isolate of the unknown yeast should be streaked to the agar surface and incubated at 25-30ºC. The medium should be examined daily for a period of up to 5 days.

INTERPRETATION OF RESULTS

C. albicans appears as smooth, circular brown-black colonies with slight mycelial fringe. There is no pigment diffusion into surrounding media and no sheen is apparent.

C. tropicalis appears as smooth, dark brown to black colonies. Slight mycelial fringe and a metallic sheen are apparent.

C. krusei appears as large, flat, shiny, wrinkled brown-black colonies with yellow pigment diffusion in surrounding media.

C. pseudotropicalis appears as medium sized, flat, wrinkled, dark reddish-brown, glistening colonies with slight mycelial fringe. No pigment diffusion is present.

C. parakrusei appears as medium sized, flat, wrinkled, glistening, dark reddish-brown, colonies with extensive yellow mycelial fringe.

C. stellatoidea appear as medium sized, flat, dark brown colonies with very light mycelial fringe.

Consult listed references for further information regarding characteristic growth patterns and morphology of Candida spp. on this medium. (6,7)

LIMITATIONS

Bacteria and yeast like fungi are mostly inhibited on this media, however, if break-through occurs they can be easily differentiated by microscopic examination.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Candida albicans
ATCC ® 60193
A 24-72hr 15-30°C Aerobic Growth; smooth tan or brown to rust colonies, no diffusion of color
Candida krusei
ATCC ® 14243
A 24-72hr 15-30°C Aerobic Growth; flat wrinkled reddish-brown colonies, yellow diffusion of color in medium, silver sheen
Candida tropicalis
ATCC ® 750
A 24-72hr 15-30°C Aerobic Growth; smooth brown to black colonies
Escherichia coli
ATCC ® 25922
B 24hr 15-30°C Aerobic Partial to complete inhibition

User Quality Control

PHYSICAL APPEARANCE

BiGGY Agar should appear opalescent with moderate precipitate evenly suspended throughout the medium, and slightly white in color.

Candidia albicans (ATCC ® 60193) colonies growing on BiGGY Agar (Cat. no. G17). Incubated aerobically for 48 hours at 35ºC.

Candidia tropicalis (ATCC ® 750) colonies growing on BiGGY Agar (Cat. no. G17). Incubated aerobically for 48 hours at 35ºC.

Candidia krusei (ATCC ® 14243) colonies growing on BiGGY Agar (Cat. no. G17). Incubated aerobically for 48 hours at 35ºC.

E. coli inhibited on BiGGY Agar

Escherichia coli (ATCC ® 25922) growth inhibited on BiGGY Agar (Cat. no. G17). Incubated aerobically for 24 hours at 35ºC.

REFERENCES

1. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

2. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

3. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

4. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I & II. American Society for Microbiology, Washington, D.C.

5. Larone, D.H. Medically Important Fungi: A Guide to Identification, American Society for Microbiology. Washington, D.C.

6. Nickerson. 1953. Journal of Infectious Diseases; 93:43.

7. Atlas, Ronald M. 1993. Handbook of Microbiological Media, CRC Press, Inc.


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