The structure of the polysaccharide of the lipopolysaccharide produced by Taylorella equigenitalis type strain (ATCC 35865)

Taylorella equigenitalis is a Gram-negative bacterium that causes venereally transmitted contagious equine metritis (CEM), and its identification and differentiation from other bacteria and Taylorella species is an important requirement for the control of CEM infection. Based on the results of NMR and MS analysis, the antigenic O-polysaccharide (O-PS) component of the lipopolysaccharide (LPS) produced by the type strain T. equigenitalis (ATCC 35865) was found to be a linear polymer composed of a repeating disaccharide unit, containing partially amidated 2,3-diacetamido-2,3-dideoxy-α-l-guluronic and 2,3-diacetamido-2,3-dideoxy-β-d-mannuronic acids, terminated with a 4-O-methylated non-reducing Gulp-NAc3NAcA residue, and has the structure.The O-PS of the type strain T. equigenitalis LPS provides a specific antigenic marker for the discrimination of the pathogen from the related type strain of T. asinigenitalis sp. nov, a phenotypically indistinguishable non-pathogenic bacterium having a serologically and structurally unrelated LPS O-antigen. The analysis of a structurally unusual core oligosaccharide of the LPS is also reported.