CRITERION™ SF (STREPTOCOCCUS FAECALIS) BROTH

Cat. no. C6930 CRITERION™ SF Broth 72gm
Cat. no. C6931 CRITERION™ SF Broth 500gm
Cat. no. C6932 CRITERION™ SF Broth 2kg
Cat. no. C6933 CRITERION™ SF Broth 10kg
Cat. no. C6934 CRITERION™ SF Broth 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ SF Broth is recommended for the cultivation and differentiation of group D enterococci from group D non-enterococci.

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

In general Enterococcus inhabit the intestinal tract of both warm and cold-blooded animals. Enterococcus faecalis and E. faecium are heat resistant and are able to survive milk pasteurization. E. faecium is especially heat tolerant. Other enterococci, especially those that are highly resistant to antibiotics, can cause serious illness to humans. Because enterococci have the ability to survive and grow in food processing plants they serve as a good index of sanitation(11)

CRITERION™ SF Broth is prepared according to the formulation developed by Hajna and Perry.(12) The medium contains 0.05% sodium azide, casein peptone, dextrose and bromcresol purple. Sodium azide acts as the selective agent by inhibiting the cytochrome oxidase enzyme in the electron transport chain. Casein peptone and dextrose supply necessary growth nutrients. Bromcresol purple serves as the color indicator.

Specimens containing group D enterococci result in the production of acid from dextrose-fermentation. Acid production is noted by a color change in the medium from purple to yellow by use of bromcresol as the pH indicator. Appearance of a yellow color change is indicative of the presence of group D enterococci.

FORMULA

Gram weight per liter: 36.0gm/L
Pancreatic Digest of Casein 20.0gm
Dextrose 5.0gm
Sodium Chloride 5.0gm
Dipotassium Phosphate 4.0gm
Monopotassium Phosphate 1.5gm
Sodium Azide 0.5gm
Bromcresol Purple 32.0mg

Final pH 6.9 +/- 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 beige to gray.

Store the prepared culture media at 2-30ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 36.0gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat as necessary to dissolve completely.

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

4. Cool to 45-50ºC.

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. K45.

LIMITATIONS

Enterococci will usually result in heavy growth and a color change within 24 hours; some strains, however, take 48 hours while others grow with no color change even after 72 hours.(4)

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
Enterococcus faecalis
ATCC ® 29212
E 24-48hr 35°C Aerobic Growth; broth turns yellow
Streptococcus pyogenes
ATCC ® 19615
E 24-48hr 35°C Aerobic Inhibited; broth remains purple

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ SF Broth powder should appear homogeneous, free-flowing, and light beige to gray in color. The prepared media should appear clear, and purple in color.

REFERENCES

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

2. Clinical Laboratory Standards Institute (CLSI - formerly NCCLS). 1996. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22-A2, Vol. 16, No. 16, Clinical Laboratory Standards Institute (CLSI - formerly NCCLS), Villanova, PA.

3. 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.

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

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

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

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

10. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

11. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

12. Hajna and Perry. 1943. Am. Jour. Publ. Health.; 33:550.


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

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