Purpose: Used for selective isolation and cultivation of Staphylococcus aureus.
Additives: Each bottle needs to be paired with 5 boxes of tellurite egg yolk enrichment solution for use.
Composition (g/L):
Tryptone 10.0
Beef Soaked Noodles 5.0
Yeast Soaking Powder 1.0
Sodium pyruvate 10.0
Glycine 12.0
Lithium chloride 5.0
Agar 20.0
PH value 7.0 ± 0.2 25 ℃
Inspection principle:
Tryptone, beef extract, and yeast extract provide carbon and nitrogen sources, vitamins, and growth factors; Sodium pyruvate and glycine stimulate the growth of Staphylococcus aureus; Lithium chloride and potassium tellurite inhibit non Staphylococcal microorganisms; Staphylococcus containing lecithinase degrades the yolk and produces a transparent ring in the colony, while lipase produces an opaque precipitation ring; Staphylococcus positive for coagulase can also reduce potassium tellurite and produce black colonies; Agar is a coagulant for culture medium.
Usage:
Weigh 63.0g of this product, heat and stir to dissolve in 950ml of distilled water. Divide each bottle into 95ml, sterilize under high pressure at 121 ℃ for 15 minutes. Before use, heat and dissolve the agar, cool to about 50 ℃, and add 5ml of thawed egg yolk potassium tellurite inoculant to every 95ml of culture medium. Shake well and pour into a sterile plate. Store in the refrigerator for no more than 48 hours before use.
Quality control and typical features
Cultivated at 36 ± 1 ℃ for 45-48 hours, the single colony of Staphylococcus aureus is circular, with a smooth, convex, and moist surface, with a diameter of 2-3mm. Grey black to black, glossy, often with light (non white) edges, surrounded by opaque circles (precipitates), and often with a clear band outside.
