Yeast extract 0.050 g Proteose Peptone (Difco no. 3) 0.050 g Casamino acids 0.050 g Glucose 0.050 g Soluble starch 0.050 g Na-pyruvate 0.030 g K2HPO4 0.030 g MgSO4 x 7 H2O 0.005 g Agar 15.00 g Distilled water 1000.00 ml Final pH 7.2; adjust with crystalline K2HPO4 or KH2PO4 before adding agar. Add agar, heat medium to boiling to dissolve agar, and autoclave for 15 min at 121° C.