Structure of the O-antigen of a novel Shigella flexneri serotype, 1d (I: 7,8)

Recently, strains of a novel Shigella flexneri serotype called 1d have been isolated from diarrheal patients in China. They are distinguished by the presence of a hitherto unknown combination of type O-factor I and group O-factor 7,8, both associated with lateral α-D-glucosyl groups on the basal linear O-polysaccharide. A serologically identical strain, 036_1d, has been constructed in the laboratory by sequential infection of serotype Y by serotype-converting bacteriophages SfX and SfI. In this work, using 1D and 2D (1)H and (13)C NMR spectroscopy, we established the following structure of the O-antigen of S. flexneri serotype 1d and demonstrated that the O-antigen of the 036_1d construct has the same structure: [structure: see text].