Structure and genetics of the O-antigen of Cronobacter sakazakii G2726 (serotype O3) closely related to the O-antigen of C. muytjensii 3270

The O-specific polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Cronobacter sakazakii G2726 (serotype O3) and studied by sugar analysis, Smith degradation, and 1H and 13C NMR spectroscopy. The following structure of the acidic O-polysaccharide was established:Figure optionsDownload as PowerPoint slideThis structure is closely related to that of the O-polysaccharide of Cronobacter muytjensii 3270, which has the same main chain and differs only in the lack of glucosylation. The O-antigen gene cluster of C. sakazakii G2726 found between the gnd and galF genes was sequenced, and the gene functions were tentatively assigned by similarity to related genes from available databases and taking into account the O-polysaccharide structure.

Figure optionsDownload as PowerPoint slideHighlights
► Cronobacter sakazakii is an important food-borne pathogen.
► We isolated an O-polysaccharide (O-antigen) from C. sakazakii G2726 (serotype 3).
► Structure of a hexasaccharide O-unit of the polysaccharide was established.
► Functions of genes for the O-antigen biosynthesis were tentatively assigned.
► The O-antigens of C. sakazakii G2726 and C. muytjensii 3270 are closely related.