Structural characterization of the O-polysaccharide antigen of Edwardsiella tarda MT 108 Original Research Article

Edwardsiella tarda, a Gram-negative bacterium, is an important cause of hemorrhagic septicemia in fish and also of gastro- and extraintestinal infections in humans. The lipopolysaccharide produced by the fish pathogenic strain E. tarda MT 108 was isolated and the structure of its antigenic O-polysaccharide component determined by the application of chemical analyses, high-resolution 1D and 2D nuclear magnetic resonance spectroscopy, and mass spectrometry. The polysaccharide was found to be a polymer of a repeating pentasaccharide unit composed of 2-acetamido-2-deoxy-d-glucose (d-GlcNAc), 2-acetamido-2-deoxy-d-galactose (d-GalNAc), d-galactose (d-Gal), l-rhamnose (l-Rha), d-galacturonic acid (d-GalA) and (2S,3R)-threonine (1:1:1:1:1:1) having the structure: