The Location of the Group Antigen of Group D Streptococcus

Abstract

Gel-diffusion precipitin tests showed that the Streptococcus group D antigen, as usually demonstrated by ring-precipitin tests, was serologically identical in all four species (Streptococcus faecalis, S. faecium, S. durans, S. bovis). Cell walls of representative cultures of all group D species had a similar chemical composition (determined by chromatography) as found by other workers. The one strain of S. bovis examined lacked galactosamine which was present in the cell walls of the other group D species. The group D specific antigen was found in the residue (cell contents) after the cell-wall fraction had been removed, unlike the group A specific antigen which forms an integral part of the cell wall.