A Noninfusion Blood Agar Base for Neisseriae, Pneumococci and Streptococci

Abstract

A blood-agar base has been developed which is simply prepd. from dehydrated materials and which possesses the growth-supporting properties of media made with fresh beef infusion and of those designed expressly for the isolation of Neisseria gonorrhoeae. When incubated routinely in a candle jar, this base makes possible the use of a single medium for the isolation of organisms ordinarily encountered in the clinical laboratory. Cultivation of the neisseriae is especially favored by the use of 0.1% corn starch and thoroughly washed granular agar (or the adequately washed Difco Noble Special Agar). [beta]-Hemolysis is produced by Group A [beta]-hemolytic streptococci which give a hemolysis on the surface of other blood agars. Incorporation of a small amt. of niacinamide slightly stimulates the growth of Hemophilus influenzae.