CRITERION™ BILE ESCULIN AZIDE MEDIA

Cat. no. C5170 CRITERION™ Bile Esculin Azide Agar 115.6gm
Cat. no. C5171 CRITERION™ Bile Esculin Azide Agar 500gm
Cat. no. C5172 CRITERION™ Bile Esculin Azide Agar 2kg
Cat. no. C5173 CRITERION™ Bile Esculin Azide Agar 10kg
Cat. no. C5174 CRITERION™ Bile Esculin Azide Agar 50kg
Cat. no. C5190 CRITERION™ Bile Esculin Azide Broth 86gm
Cat. no. C5191 CRITERION™ Bile Esculin Azide Broth 500gm
Cat. no. C5192 CRITERION™ Bile Esculin Azide Broth 2kg
Cat. no. C5193 CRITERION™ Bile Esculin Azide Broth 10kg
Cat. no. C5194 CRITERION™ Bile Esculin Azide Broth 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Bile Esculin Azide Media are recommended for the isolation and differentiation of group D streptococci from non-group D.

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

Esculin hydrolysis was first described by Rochaix in 1924.(8) Swan first introduced the use of Bile Esculin Agar in 1954.(9) Facklam and Moody, in 1970, determined that the use of the bile esculin test was a reliable way of identifying group D streptococci from non-group D streptococci.(3) When using BEA in biochemical testing of group D streptococci, they found that all group D streptococci will blacken this medium.(3) Other researchers have used BEA for the presumptive identification of Enterobacter, Klebsiella and Serratia.

This medium contains esculin, ferric citrate to provide ferric ions, and 1% oxbile to inhibit most other strains of non-group D streptococci. Sodium azide is incorporated into the medium to inhibit gram-negative bacteria. Esculin is hydrolyzed by group D streptococci to form dextrose and esculetin. This compound reacts with the ferric ions contained within the medium, turning the medium dark brown to black. Thus, the tolerance to the presence of bile and the hydrolysis of esculin provide the means to presumptively identify group D streptococci.

FORMULA

Bile Esculin Azide Agar:
Gram weight per liter: 61.7gm/L
Pancreatic Digest of Casein 20.0gm
Oxbile (Oxgall) 10.0gm
Yeast Enriched Meat Peptone 10.0gm
Sodium Chloride 5.0gm
Esculin 1.0gm
Ferric Ammonium Citrate 0.5gm
Sodium Azide 0.15gm
Agar 15.0gm

Final pH 7.1 +/- 0.2 at 25ºC.

Bile Esculin Azide Broth:
Gram weight per liter: 43.0gm/L
Pancreatic Digest of Casein 16.0gm
Oxbile (Oxgall) 10.0gm
Yeast Enriched Meat Peptone 9.5gm
Sodium Chloride 5.0gm
Sodium Citrate 1.0gm
Esculin 1.0gm
Ferric Ammonium Citrate 0.5gm
Sodium Azide 0.25gm

Final pH 7.1 +/- 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.

Store the prepared culture media at 2-30ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

Bile Esculin Azide Agar:

1. Suspend 57.8gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely. Avoid overheating.

3. Sterilize in the autoclave at 121ºC. for 15 minutes. Overheating may cause the media to darken.

4. Cool to 50-55ºC and dispense into sterile petri dishes. If tubed, allow the medium to solidify in the slanted position.

Bile Esculin Azide Broth:

1. Suspend 43.0gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat as necessary to dissolve completely. Avoid overheating.

3. Dispense into autoclavable tubes.

4. Sterilize in the autoclave at 121ºC. for 15 minutes. Overheating may cause the media to darken.

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. G11 (agar) and K11 (broth).

MATERIALS REQUIRED BUT NOT PROVIDED

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

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Bile Esculin Azide Agar and Bile Esculin Azide Broth:
Enterococcus faecalis
ATCC® 29212
A 24-48hr 35°C Aerobic Growth; blackening of media around colonies
Streptococcus pyogenes
ATCC® 19615
B 24-48hr 35°C Aerobic Partial to complete inhibition
Escherichia coli
ATCC® 25922
B 24-48hr 35°C Aerobic Partial to complete inhibition; small colorless colonies

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Bile Esculin Azide Agar powder should appear homogeneous, free-flowing, and tan in color. CRITERION™ Bile Esculin Azide Broth powder should appear homogeneous, free-flowing, and tan in color. The prepared media should appear clear, and medium to dark amber, with a slight bluish-tinge in color. The agar may be slightly opalescent.

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. Facklam, R.R. and M.D. Moody. 1970. Appl. Microbiol.; 20:245.

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

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

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

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

8. Rochaix. 1924. Cr. Soc. Biol., Paris; 90:771.

9. Swan, A. 1954. J. Clin. Path.; 7:160-163.


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

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