Progress toward developing a carbohydrate-conjugate vaccine against Clostridium difficile ribotype 027: synthesis of the cell-surface polysaccharide PS-I repeating unit.

Clostridium difficile strain ribotype 027 is a hypervirulent pathogen that is responsible for recent, severe outbreaks of serious nosocomial infections. As a foundation for the development of a preventative carbohydrate-based vaccine, we have synthesized a pentasaccharide cell wall repeating unit from PS-I unique to this strain, by the linear assembly of four monosaccharide building blocks.