A Quick Method for Preparing Homogeneous Suspensions of Hemolytic Streptococcus Antigens for Agglutination Testing

摘要

It is well known that the greatest single difficulty encountered in the application of the agglutination and agglutinin absorption tests to the hemolytic streptococcus, is the fact that the hemolytic streptococcus almost invariably grows in liquid media, with sedimentation of the cells, leaving at the end of eighteen to twenty-four hours incubation, a clear supernatant fluid, whereas a cloudy homogeneous suspension of cells is essential for the agglutination test.The belief that the spontaneous clumping of the streptococci in broth media is due to excessive acidity produced during the growth of the bacteria brought about the adaptation of special methods of growing these organisms. One of the methods is to cultivate the organisms in calcium-carbonate-glucose broth in which the carbonate is supposed to neutralize the acidity in the broth culture. Another method, developed by Dochez, Avery and Lancefield, depends on the use of a special sugar-free broth containing buffer. The buffer used is dibasic potassium phosphate.