The structure of the O-antigen of Cronobactersakazakii HPB 2855 isolate involved in a neonatal infection

Abstract

Strains of Cronobacter sakazakii (previously known as Enterobacter sakazakii) are medically recognized important Gram-negative bacterial pathogens that cause enterocolitis, septicemia, and meningitis, with a high mortality rate in neonates. The structure of their O-antigens, that form part of their somatic lipopolysaccharide (LPS) components, is of interest for their chemical and serological identification and their relationship to virulence. The O-polysaccharide (O-PS) of C. sakazakii HPB 2855 (SK 81), a strain isolated from an infant at the Hospital for Sick Children in Toronto in 1981, was shown to be a polymer of a partially O-acetylated-repeating hexasaccharide unit composed of d-glucose, d-galacturonic acid, 2-acetamido-2-deoxy- d-galactose, and l-rhamnose (1:1:1:3). From composition and methylation analysis, and the application of 1D and 2D 1H and 13C NMR spectroscopy, the O-PS was determined to be a polymer of a repeating oligosaccharide unit having the structure: [Display omitted]