Technical Data
Media
Staphylococcus Selective Agar (Powder)
S7965-30
Microbiological Grade
Storage RT    Shipping RT
Formulation (g/L)
Peptone from casein10.0
Meat extract5.0
Yeast extract1.0
Sodium pyruvate10.0
Glycine12.0
Lithium chloride5.0
Agar15.0
Optional:
Egg-yolk tellurite emulsion 50ml; if required, sulphamethazine 0.05 g/L
Selective medium for Staphylococcus recovery from food products and clinical material.

Mode of Action:
This medium contains lithium chloride and tellurite to inhibit the growth of accompanying microbial flora, whereas pyruvate and glycine selectively stimulate the growth of staphylococci.
Staphylococcus colonies show two characteristic features when grown in this opaque medium (opaque, because of its egg-yolk content)
a) characteristic zones and rings are formed as a result of lipolysis and proteolysis,
b) reduction of tellurite to tellurium produces a black coloration.
The egg-yolk reaction and tellurite reduction are usually found to occur together with a positive coagulase reaction and can thus serve as an index for the latter.

Stadhouders et al. (1976) recommend that egg-yolk should be replaced with blood plasma, if coagulase-positive staphylococci are to be detected directly. Smith and Baird-Parker (1964) recommend the addition of sulfamethazine to suppress the growth and swarming of Proteus species.


Suspend 58g in 0.95L, autoclave (15 min at 121C). Cool to 45-50C, mix in 50ml Egg-yolk Tellurite Emulsion and, if required, 50mg sulfamethazine/litre. Pour plates. pH: 6.8 0.2 at 25C.

The plates are opalescent and yellowish-brown in color. The ready-to-use culture medium can be stored in the refrigerator (approx. 4C) for up to 1 month.Experimental Procedure and Evaluation:Dilute the sample material and spread thinly on the surface of the culture medium.Incubation: 24-48 hours at 35C aerobically.


Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.