Elucidation of the structure and characterization of the gene cluster of the O-antigen of Cronobacter sakazakii G2592, the reference strain of C. sakazakii O7 serotype.

The O-specific polysaccharide from the lipopolysaccharide of Cronobacter sakazakii G2592 was studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy, and the following structure of the pentasaccharide repeating unit was established: [See figure in text]. This structure is unique among the known bacterial polysaccharide structures, which is in accord with classification of strain G2592 into a new C. sakazakii serotype, O7. It is in agreement with the O-antigen gene cluster of this strain, which was found between the housekeeping genes JUMPStart and gnd and characterized by sequencing and tentative assignment of the gene functions.