Five of the strains of E. coli are related to only one of the S. dysenteriae strains. Three of the coli are related to two of the strains of S. dysenteriae, four are related to three of the S. dysenteriae strains, and one, A-H6, is related to all.
1939 January, Thomas T. Mackie, “The Specificity of the Agglutinin Reaction for Shigella dysenteriae: II. Agglutinin Absorption Relationships between Shigella dysenteriae and Escherichia coli”, in Journal of Bacteriology, volume 37, number 1, archived from the original on 10 June 2020, page 47