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 (1)H and (13)C NMR spectroscopy. The following structure of the acidic O-polysaccharide was established: [structure: see text]. This 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.