HardyCHROM™ Candida

Cat. no. G301 HardyCHROM™ Candida, 15x100mm Plate, 18ml 10 plates/bag

INTENDED USE

HardyCHROM™ Candida is a selective medium recommended for the isolation and identification of yeasts. This medium also allows for the differentiation of C. albicans , C. tropicalis and C. krusei based on differences in colony morphology and color. This medium facilitates the detection of mixed yeast cultures.

SUMMARY AND PRINCIPLES

HardyCHROM™ Candida is a selective and differential medium containing chromogenic substrates. After degradation by specific enzymes, the substrates release different colored compounds. Certain species or groups of organisms can then be differentiated with a minimum number of confirmatory tests.

Colonies of C. albicans appear green to dark metallic green, C. tropicalis colonies appear medium blue to dark metallic blue with a blue halo, and C. krusei colonies appear flat, often rough or crenated, and pink to medium pink in color. Other species appear pink, often with a darker mauve center ( C. glabrata and other species). Other yeasts may appear white to pink.

Additionally, HardyCHROM™ Candida can be used in conjunction with Rapid Trehalose Broth (Cat. no. Z205) or GlabrataQuick™ (Cat. no. Z298) to aid in the identification of C. glabrata . When HardyCHROM™ Candida is used as the primary plating medium, only colonies that morphologically (pink, often with a darker mauve center) resemble C. glabrata should be tested for trehalose assimilation.

HardyCHROM™ Candida contains glucose and selected peptones as a nutrient supply. Chromogenic substrates are incorporated to enable the production of different colored compounds when degraded by specific enzymes formed by the yeast. Chloramphenicol is added as an inhibitory agent against the growth of most bacteria, which may be present in the sample.

FORMULA

Ingredients per liter of deionized water:*

Glucose 20.0gm
Peptone 10.0gm
Chromogenic Mixture 2.0gm
Chloramphenicol 0.5gm
Agar 15.0gm

Final pH 6.1 +/- 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: Consult listed references for information on specimen collection. (1-8) 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 the listed references for information regarding the processing of specimens. (1-9)

Protect media from light during storage and incubation as the product is light sensitive.

Method of Use: Allow the plates to warm to room temperature. The agar surface should be dry prior to inoculating. Inoculate and streak the specimen as soon as possible after collection. If the specimen to be cultured is on a swab, roll the swab over a small area of the agar surface. Streak for isolation with a sterile loop. Incubate plates in an inverted position, protected from the light, aerobically at 35ºC. with increased humidity for 48 hours.

Most pathogenic strains of yeast grow at 35ºC. Some strains, other than C. albicans , C. krusei , C. glabrata and C. tropicalis , may fail to grow at 35ºC. If cultivation of all yeast strains is desired, the recommended incubation temperature is 30ºC. for up to 7 days, since the lower temperature will slow the growth.

INTERPRETATION OF RESULTS

Examine plates for colonies showing typical morphology and color.

Some strains may show sufficient growth and color development to be read at 24 hours, however, all plates should be incubated for at least 48 hours to allow for adequate color development. Colors will intensify with age.

A medium size, smooth, green to dark metallic green colored colony at 48 hours is identified as Candida albicans . Colonies will appear light green at 24 hours.

A medium size, smooth, medium blue to dark metallic blue colored colony, with a blue halo, at 48 hours is identified as Candida tropicalis . Colonies will appear blue to blue-pink at 24 hours.

A large, flat, spreading, often rough or crenated, pink to medium pink colored colony is identified as Candida krusei .

A medium size, smooth, pink colored colony, often with a darker mauve center, is presumptively identified as Candida glabrata ; thus a Rapid Trehalose test is needed (see "Limitations" below).

Other yeasts are generally small, white to pink colored colonies.

LIMITATIONS

Candida spp. other than C. glabrata may present white to pink colored colonies on HardyCHROM™ Candida which is why C. glabrata must be confirmed using Trehalose assimilation. Refer to the Rapid Trehalose Broth (Cat. no. Z205) or GlabrataQuick™ (Cat. no. Z298) technical information sheet for additional information concerning the definitive identification of C. glabrata . Colonies that are 24 hours old may be used to test for rapid Trehalose assimilation.

Some strains of yeast, other than C. albicans , C. krusei , C. tropicalis , and C. glabrata , may fail to grow at 35 degrees C. If cultivation of all yeast strains is desired, the recommended incubation is 30 degrees C. for up to 7 days.

Isolates of C. dubliniensis will grow on this medium and will produce colors similar to or slightly different from C. albicans on primary isolation. The color variation will be lost upon subculture, so additional testing may be required to differentiate the two species.

This product is not intended for the isolation and identification of Cryptococcus spp.

Color-blind individuals may encounter difficulty in distinguishing the color differences on HardyCHROM™ Candida.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, Rapid Trehalose Broth (Cat. no. Z205), GlabrataQuick™ (Cat. no. Z298), incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results at
24 hours
Results at
48 hours
Time Temperature Atmosphere
Candida albicans
ATCC ® 10231
B 24-48hr 35°C Aerobic Growth; smooth, light green colonies Growth; smooth, emerald green to dark metallic green colonies
Candida tropicalis
ATCC ® 750
B 24-48hr 35°C Aerobic Growth; smooth, blue to blue-pink colonies Growth; smooth, medium blue to dark metallic blue colonies, with a blue halo
Candida krusei
ATCC ® 14243
B 24-48hr 35°C Aerobic Growth; flat, pink to medium pink, spreading, colonies Growth; flat, pink to medium pink, large, spreading, rough, crenated colonies
Candida glabrata
ATCC ® 66032
B 24-48hr 35°C Aerobic Growth; smooth, pink colonies Growth; smooth, pink colonies, often with a darker mauve center
Escherichia coli
ATCC ® 25922
B 24hr 35°C Aerobic Partial to complete inhibition Partial to complete inhibition

USER QUALITY CONTROL

PHYSICAL APPEARANCE

HardyCHROM™ Candida should appear transparent, and white to light amber in color.

C. albicans growing on HardyCHROM™ Candida

Candida albicans (ATCC ® 10231) colonies growing on HardyCHROM™ Candida (Cat. no. G301). Incubated aerobically for 48 hours at 35ºC.

C. tropicalis growing on HardyCHROM™ Candida

Candida tropicalis (ATCC ® 750) colonies growing on HardyCHROM™ Candida (Cat. no. G301). Incubated aerobically for 48 hours at 35ºC.



C. krusei growing on HardyCHROM™ Candida

Candida krusei (ATCC ® 14243) colonies growing on HardyCHROM™ Candida (Cat. no. G301). Incubated aerobically for 48 hours at 35ºC.

C. glabrata growing on HardyCHROM™ Candida

Candida glabrata (ATCC ® 66032) colonies growing on HardyCHROM™ Candida (Cat. no. G301). Incubated aerobically for 48 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. Ajello, et al. 1963. CDC Laboratory Manual for Medical Mycology, PHS Publication No. 994, U.S. Government Printing Office, Washington, D.C.

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

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

5. Haley, L.D., et al. 1980. Cumitech 11; Practical Methods for Culture and Identification of Fungi in the Clinical Microbiology Laboratory, Coordinating ed., J.C. Sherris. American Society for Microbiology, Washington, D.C.

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

7. Kwon-Chung, K.J., and J.E. Bennett. 1992. Medical Mycology. Lea and Febiger, Malvern, PA.

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

9. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

10. Land, G., et al. Sept. 1996. Journal of Clinical Microbiology; Vol. 34, No. 9, p. 2300-2303.

ATCC is a registered trademark of the American Type Culture Collection.

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