CRITERION™ MYCOBIOTIC AGAR

Cat. no. C6430 CRITERION™ Mycobiotic Agar 65.2gm
Cat. no. C6431 CRITERION™ Mycobiotic Agar 500gm
Cat. no. C6432 CRITERION™ Mycobiotic Agar 2kg
Cat. no. C6433 CRITERION™ Mycobiotic Agar 10kg
Cat. no. C6434 CRITERION™ Mycobiotic Agar 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Mycobiotic Agar is recommended for use in the selective isolation and recovery of pathogenic fungi and dermatophytes.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Leach, Ford and Whiffen described the use of cycloheximide for the inhibition of saprophytic fungi.(1,2) Cooke et al., employed the use of chloramphenicol to various media to inhibit bacterial growth.(3,4) Researchers later found that the addition of both cycloheximide and chloramphenicol achieved more complete selectivity against the growth of saprophytic fungi and bacteria.(5,6) Therefore, the incorporation of both of these antimicrobics into the soybean basal medium of Mycobiotic Agar promotes its selectivity. Consequently, Georg recommends the exclusive use of Mycobiotic Agar for isolating dermatophytes, which are not sensitive to cycloheximide or chloramphenicol, and in parallel to media without antibiotics for isolating fungi which may cause systemic disease.(7)

CRITERION™ Mycobiotic Agar is a selective medium consisting of peptones, dextrose, cycloheximide and chloramphenicol. The basal medium is soybean meal. Peptones from soybean meal provide the nutritive properties necessary for growth. Dextrose serves as the energy source. Cycloheximide inhibits most saprophytic fungi while chloramphenicol acts as a broad-spectrum antimicrobic. Chloramphenicol inhibits a wide variety of gram-positive and gram-negative bacteria

FORMULA*

Gram weight per liter: 35.6gm/L
Pancreatic Digest of Soybean Meal 10.0gm
Dextrose 10.0gm
Cycloheximide 0.5gm
Chloramphenicol 0.05gm
Agar 15.0gm

Final pH 6.5 +/- 0.2 at 25ºC.

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

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original tan to light beige.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 32.6gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat to boiling to dissolve completely.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC. and aseptically dispense into sterile containers. Product may be autoclaved in tubes if desired.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. W50.

LIMITATIONS

The antimicrobics in this medium may result in the inhibition of some pathogenic fungi that cause systemic disease. It is recommended that a non-selective media be set-up in parallel for optimum recovery.

It is recommended that media containing cycloheximide be incubated at room temperature (25-30ºC.) for best results.

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
Trichophyton mentagrophytes
ATCC® 9533
G 7 days 15-30°C Aerobic Growth
Candida albicans
ATCC® 10231
A 7 days 15-30°C Aerobic Growth
Escherichia coli
ATCC® 25922
B 7 days 15-30°C Aerobic Partial to complete inhibition
Aspergillus brasiliensis
formerly A. niger
ATCC® 16404

G 7 days 15-30°C Aerobic Partial to complete inhibition

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Mycobiotic Agar powder should appear homogeneous, free-flowing, and tan to light beige in color. The prepared media should appear slightly opalescent, and light amber in color.

REFERENCES

1. J. Am. Chem. Soc.; 69:474, 1947.

2. J. Bacteriology; 56:283, 1948.

3. Antibiotics and Chemotherapy; 4:657, 1954.

4. J. Am. Med. Assoc.; 160:537, 1956.

5. J. Chron. Dis.; 5:545, 1957.

6. J. Lab. and Clin. Med.; 55:116, 1960.

7. Georg, L.K., E.S. McDonough, L. Ajello, and S. Brinkman. 1960. In vitro effects of antibiotics on yeast phase of Blastomyces dermatitidis and other fungi. J. Lab. & Clin. Med.; 55:116-19.

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

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

10. St. Germain, Guy, et al. 1996. Identifying Filamentous Fungi. Star Publishing Company, Belmont, CA.

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

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

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

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

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

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