In one aspect, the invention relates to an immunogenic composition comprising modified O-polysaccharide molecules derived fromE. colilipopolysaccharides and conjugates thereof. Multivalent vaccines may be prepared by combining two or more monovalent immunogenic compositions for differentE. coliserotypes. In one embodiment, the modified O-polysaccharide molecules are produced by a recombinant bacterium that includes a wzz gene.在一個態樣中，本發明係關於一種免疫原性組合物，其包含衍生於大腸桿菌(E. coli)脂多醣之經修飾之O-多醣分子及其共軛物。多價疫苗可藉由組合針對不同大腸桿菌血清型之兩種或更多種一價免疫原性組合物來製備。在一個實施例中，該等經修飾之O-多醣分子係由包括wzz基因之重組細菌產生。
