A selective medium for isolation of gram positive bacteria. Most often utilized with blood added. Eliner, et al. added colistin and nalidixic acid to Columbia Agar to suppress the growth of Gram negative bacteria. The addition of 5-10% sheep red blood cells to the base demonstrates hemolytic patterns of the Staphylococci and Streptococci.||Appearance:|Light beige, homogeneous, free flowing powder||Solubility:|Yellow, slightly opaque after autoclaving||pH:|As Reported||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.