Lancefield’s groups

Recent studies of the exact nutritional requirements of various strains of hemol3 tic streptococci have resulted in their cultivation on media of completely defined chemical composition (232, 342, 449). Riboflavin has been included in the media in all cases, on the grounds of its known behavior as a growth factor for other bacteria, but it has not been shown always to be an essential component of the media. For the strains of hemolytic streptococci grown by Woolley and Hutchings (449) and by Schuman and Farrell (342), which included members of Lancefield s groups A, B, C, D, riboflavin was essential also for Streptococcus fecalis (342). Earlier work, before these media of defined composition had been worked out, had indicated the important part plaj ed by riboflavin in the nutrition of various strains of hemolytic streptococci (290,448). 

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