Chemical structure of the O-polysaccharides isolated from Cronobacter turicensis sequence type 5 strains 57, 564, and 566

The Cronobacter spp. are Gram-negative bacterial pathogens that can cause infections in all age groups, and have a high mortality rate in neonates due to necrotizing enterocolitis and meningitis. Recent genotyping studies have revealed a strong clonal lineage in the genus, but this has not been compared with physiological traits. The O-polysaccharides (OPS) were isolated from three C. turicensis sequence type 5 strains (57, 564, and 566) and structurally characterized using 1H and 13C NMR spectroscopy, including two-dimensional DQF-COSY, TOCSY, ROESY, and HSQC analysis. Further compositional determination was undertaken using classical chemical methods followed by GLC, and GLC-MS analysis. The repeating unit of the isolated O-polysaccharides consists of GlcNAc, Rha, Glc, and had the structure shown below and therefore complemented the sequence type.