CORN MEAL AGAR WITH TWEEN ® 80

Cat. no. W10 Corn Meal Agar with Tween® 80,
15x100mm Plate, 26ml
10 plates/bag
Cat. no. G101 Corn Meal with Tween® 80,
15x60mm Plate, 13ml
10 plates/bag
Cat. no. J48 Corn Meal with Tween® 80,
15x100mm Biplate, 13ml/13ml
10 plates/bag
Cat. no. Q12 Corn Meal Agar with Tween® 80,
20x125mm Tube, 18ml Deep
20 or 100 tubes/box

INTENDED USE

Hardy Diagnostics Corn Meal Agar with Tween® 80 is recommended for use in the cultivation of fungi and for the inducement of chlamydospore formation by Candida albicans.

SUMMARY

Corn Meal Agar is an enrichment medium developed by Hazen and Reed for use in the cultivation of fungi.(11) Walker and Huppert, in 1960, found that the addition of Tween® 80 to Corn Meal Agar resulted in rapid and abundant chlamydospore formation.(10) The medium consists of corn meal infusion and agar. Growth nutrients are provided by the infusion product. Tween® 80, a mixture of oleic esters, stimulates the production of chlamydospores by C. albicans, C. stellatoidea  and occasionally C. tropicalis.(2,10)

Corn Meal Agar with Tween® 80 tubed media are used for the maintenance of fungal stock cultures.

FORMULA

Ingredients per liter of deionized water:*

Corn Meal Infusion 2.0gm
Tween ® 80 7.0ml
Agar 15.0gm

Final pH 6.2 +/- 0.3 at 25ºC.

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

STORAGE AND SHELF LIFE

Storage: Upon receipt store plates (Cat. nos. W10, G101 and J48) at 2-8ºC and tubes (Cat. no. Q12) at 2-30ºC. Store products 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. Products are light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.

PRECAUTIONS

PROCEDURE

Specimen Collection: This media is not intended for primary isolation. It is for use in characterizing pure cultures. Consult listed references for information regarding the processing and inoculation of specimens.(1,2,4-6)

Before Use: If using Corn Meal Agar Deeps, liquify the medium by heating in boiling water. Cool medium to 45-50ºC and pour into sterile petri dishes. Allow to solidify for at least 30 minutes.

1. Using an inoculating needle, obtain visible paste of the organism. Draw the needle through the agar making two perpendicular lines in the shape of an "x".

2. Flame a coverslip and allow it to cool. Once coverslip has cooled, place over the central area of the "x" in order to reduce oxygen tension. Reduced oxygen tension stimulates chlamydospore production. Leave some growth uncovered.

3. Seal the plate with tape or MycoSeals™ (Cat. no. SS9225) and incubate aerobically at room temperature (25-30ºC) for up to 72 hours in the dark. Examine daily for typical colonial growth and morphology.

4. Invert the plate and examine microscopically using a low power objective (10X). View along the edge of the coverslip for detection of chlamydospore formation.

5. Follow steps one through four of the above procedure for the examination of sporulation of molds.(6,7) Incubate until mold is visible and mount coverslip in glycine. Examine microscopically for characteristic structures.

INTERPRETATION OF RESULTS

Using low power magnification, examine for the presence of budding cells, hyphae, blastospores, and chlamydospores. Most strains of C. albicans and C. stellatoidea form typical chlamydospores after 24-48 hours incubation. Examine daily for up to four days.(8) C. dubliniensis will also form chlamydospores, but in clusters, rather than singles as with the C. albicans.

LIMITATIONS

Chlamydospore formation is inhibited at 30-37ºC.(12) A temperature of 25ºC is recommended for the best results.

A non-selective and selective medium should be inoculated for isolation of fungi from potentially contaminated specimens.

Repeated subculturing of some Candida strains result in a loss of their ability to produce chlamydospores.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, swabs, applicator sticks, other culture media, incinerators, 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 ® 10231
C 24-72hr 15-30°C Aerobic Growth; hyphae, budding cells, and chlamydospores seen
Candida glabrata
ATCC ® 66032
C 24-72hr 15-30°C Aerobic Growth; no chlamydospores seen

User Quality Control

PHYSICAL APPEARANCE

Corn Meal Agar with Tween® 80 should appear slightly opalescent, and white in color.

C. albicans growing on Corn Meal Agar with Tween®

Candida albicans (ATCC® 10231) colonies growing on Corn Meal Agar with Tween® 80 (Cat. no. G101). Incubated aerobically for 72 hours at 15-30ºC. Shown with coverslip.

C. albicans growing on Corn Meal Agar with Tween®

Microscopic image at 100x of chlamydospores from Candida albicans (ATCC® 10231) grown on Corn Meal Agar with Tween® 80 (Cat. no. G101).

C. albicans growing on Corn Meal Agar with Tween®

Microscopic image at 500x of chlamydospores from Candida albicans (ATCC® 10231) grown on Corn Meal Agar with Tween® 80 (Cat. no. G101).

Corn Meal Agar with Tween®

Uninoculated plate of Corn Meal Agar with Tween® 80 (Cat. no. W10).

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. Cumitech 11: Practical Methods for Culture and Identification of Fungi in the Clinical Microbiology Laboratory. 1980. American Society for Microbiology, Washington, D.C.

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

6. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

7. Campbell, M.C. and J.L. Stewart. 1980. The Medical Mycology Handbook, John Wiley & Sons, New York.

8. McGinnins. 1980. Laboratory Handbook of Medical Mycology, Academic Press, New York.

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

10. Walker and Huppert. 1960. Tech. Bull. Reg. Med. Technol.; 30:10.

11. Hazen, E.L. and F.C. Reed. 1955. Monograph Laboratory Identification of Pathogenic Fungi Simplified, American Lecture Series, Publ. No. 253, p. 100. Charles C. Thomas, Springfield, IL.

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


ATCC is a registered trademark of the American Type Culture Collection.
Tween is a registered trademark of ICI Americas, Inc.

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