CRITERION™ VOGEL AND JOHNSON AGAR BASE

Cat. no. C7280 CRITERION™ Vogel and Johnson Agar Base 120gm
Cat. no. C7281 CRITERION™ Vogel and Johnson Agar Base 500gm
Cat. no. C7282 CRITERION™ Vogel and Johnson Agar Base 2kg
Cat. no. C7283 CRITERION™ Vogel and Johnson Agar Base 10kg
Cat. no. C7284 CRITERION™ Vogel and Johnson Agar Base 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Vogel and Johnson Agar Base, with added potassium tellurite, is a selective agar medium used for the detection of coagulase-positive, mannitol-positive Staphylococcus aureus strains.

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

Vogel and Johnson Agar was developed by Vogel and Johnson as a modification of the Tellurite Glycine Agar medium described by Zebovitz, Evans, and Niven.(7,8) Vogel and Johnson increased the mannitol content of the Tellurite Glycine Agar and added a pH indicator, phenol red. The pH indicator enables the detection of mannitol fermentation, a differentiating characteristic of most strains of Staphylococcus aureus. Coagulase-positive strains of S. aureus form characteristic black colonies on the medium due to the reduction of tellurite. Colonies of mannitol-fermenting strains will be surrounded by a yellow zone. The Association of Analytical Chemists (AOAC) has recommended the medium for detection of S. aureus in foods.(5)

Due to the high selectivity and sensitivity of the medium, Vogel and Johnson Agar may be used for the rapid detection of the S. aureus in clinical specimens when the detection of the etiologic agent is of singular importance. Other microorganisms are easily distinguished by their inability to produce black colonies. Selective agents incorporated into the medium are glycine and lithium chloride, which inhibit growth of most other organisms. Potassium tellurite is added to the prepared medium. The tellurite salt is an inhibitory agent and is easily reduced by coagulase-positive staphylococci, leaving a black precipitate in the colony.

FORMULA

Gram weight per liter: 60.0gm/L
Pancreatic Digest of Casein 10.0gm
Glycine 10.0gm
Mannitol 10.0gm
Yeast Extract 5.0gm
Dipotassium Phosphate 5.0gm
Lithium Chloride 5.0gm
Phenol Red 25.0mg
Agar 15.0gm

Final pH 7.2 +/- 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 light reddish-beige.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 60.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely.

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

4. Cool to 45-50ºC. and aseptically add 20ml of a 1% potassium tellurite solution or 5.7ml of a 3.5% potassium tellurite solution.

5. Mix thoroughly before dispensing.

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. G193.

LIMITATIONS

If tellurite is reduced but mannitol is not fermented, the medium surrounding colonies may be a deeper red color. This occurs due to the utilization of proteins in the medium and results in an increase in alkalinity.(3)

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, incubators, and potassium tellurite, etc. are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Staphylococcus aureus
ATCC ® 25923**
A 18-48hr 35°C Aerobic Growth; black colonies with yellow zones
Staphylococcus epidermidis
ATCC ® 12228
B 18-48hr 35°C Aerobic Growth, poor; gray-black colonies
Escherichia coli
ATCC ® 25922**
B 18-48hr 35°C Aerobic Partial to complete inhibition
Enterococcus faecalis
ATCC ® 29212
B 18-48hr 35°C Aerobic Partial to complete inhibition

** Recommended QC strains for User Quality Control according to the CLSI document M22 when applicable.

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Vogel and Johnson Agar Base powder should appear homogeneous, free-flowing, and light reddish-beige in color. The prepared media should appear slightly opalescent, and reddish-orange in color.

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

3. MacFaddin, J.F. 1985. Media for Isolation, Cultivation, Identification, Maintenance of Bacteria, Vol. I. Williams & Wilkins, Baltimore, MD.

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

5. The Official Compendia of Standards. 2008. USP27-NF22. United States Pharmacopeial Convention, Rockville, MD.

6. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA.
http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm.

7. Vogel, R.A. and M.J. Johnson. 1960. Public Health Lab; 18:131.

8. Zebovitz, E., et al. 1955. J. Bacteriol.; 70:686.


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

062916gr