CRITERION™ SELECTIVE STREP AGAR BASE

Cat. no. C6890 CRITERION™ Selective Strep Agar Base 88gm
Cat. no. C6891 CRITERION™ Selective Strep Agar Base 500gm
Cat. no. C6892 CRITERION™ Selective Strep Agar Base 2kg
Cat. no. C6893 CRITERION™ Selective Strep Agar Base 10kg
Cat. no. C6894 CRITERION™ Selective Strep Agar Base 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Selective Strep Agar Base is recommended for the selective isolation of all species of streptococci.

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

CRITERION™ Selective Strep Agar Base is designed to inhibit gram-negative bacilli and staphylococci, thereby allowing for the isolation, subculture, and identification of pathogenic streptococci (groups A, B, C, F and G), including beta-hemolytic streptococci and S. pneumoniae.

Tryptic Soy Agar is the basal medium for CRITERION™ Selective Strep Agar Base. Organic nitrogen, particularly amino acids and long-chained peptides, are supplied by the casein peptones, rendering the medium highly nutritious. Osmotic equilibrium is maintained by sodium chloride. Sheep blood (5%) is added to facilitate growth and to detect hemolytic activity. Selective agents are present in the media to suppress much of the oral flora, including coliforms, staphylococci, Micrococcus, Haemophilus and Neisseriaspecies.

FORMULA

Gram weight per liter: 44.0gm/L
Pancreatic Digest of Casein 15.0gm
Papaic Digest of Soybean Meal 7.5gm
Sodium Chloride 5.0gm
Nucleic Acid 3.0gm
Selective Agents 15.3mg
Agar 13.5gm

Final pH 7.3 +/- 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.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 44.0gm 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.

5. Aseptically add 50ml of sterile defibrinated sheep blood. Stir gently while 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. A10.

LIMITATIONS

Prepared Selective Strep Agar with added sheep blood is designed to grow all species of streptococci, which would include some normal respiratory flora, such as S. viridans.

Unless a provision is made to reduce oxygen tension, approximately 2% of group A streptococci may be missed if incubated aerobically. It is recommended that several stabs be made into the medium upon inoculation.(2) Incubation in increased CO2 or anaerobically is recommended.

Prepared Selective Strep Agar with added sheep blood may be inhibitory to certain rare strains of streptococci.

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
Streptococcus pyogenes
ATCC® 19615
A 24hr 35°C CO2** Growth; beta-hemolysis
Streptococcus pneumoniae
ATCC® 6305
A 24hr 35°C CO2** Growth; alpha-hemolysis
Escherichia coli
ATCC® 25922
B 24hr 35°C CO2** Inhibited
Staphylococcus epidermidis
ATCC® 12228
B 24hr 35°C CO2** Inhibited

User Quality Control

** Atmosphere of incubation is enriched with 5-10% CO2.

PHYSICAL APPEARANCE

CRITERION™ Selective Strep Agar Base powder should appear homogeneous, free-flowing, and light beige in color. The prepared media without added blood should appear clear to a trace hazy, and amber in color. The prepared media with added sheep blood should appear opaque, and cherry red 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. 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. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

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

6. Pacifico, L., et al. 1995. Journal of Clinical Micro.; 33; 9:2480-2482. American Society for Microbiology.


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

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