Clostridium difficile is a Gram-positive bacterium that is the most common cause of hospital-associated and antimicrobial-associated diarrhea in humans. Monteiro and co-workers have discovered that C. difficile expresses three cell-surface polysaccharides, named PS-I, PS-II and PS-III. Interestingly, PS-I was determined to be present in a ribotype 027 strain, the ribotype responsible for recent deadly outbreaks worldwide. In this work, the total chemical synthesis of the PS-I pentasaccharide with a linker molecule by a linear synthesis strategy from four monosaccharide building blocks is described: α-L-Rhap-(1→3)-β-D-Glcp-(1→4)-α-D-Glcp-(1→2)-α-D-Glcp-(1→O(CH2)5NH2 3 ↑ 1 α-L-Rhap The synthesized PS-I pentasaccharide will be conjugated to a protein carrier for evaluation as an anti-C. difficile glycoconjugate vaccine.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nutrition and Food Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 370-377. / by James Chi-Yung Leung. / Ph.D.