Immunochemical characterization of lipopolysaccharides of Citrobacter chemotypes CC-G and CC-H

Lipopolysaccharides of Citrobacter serotypes 04, 027 and 036 indicate strong cross-reactivity in passive hemagglutination and their O-specific chains are homopolymers of (beta 1----2)--linked 4-deoxy-D-arabinohexose. Citrobacter serotype 023 cannot be placed in chemotype CC-H, since its O-specific polysaccharide does not contain 4-deoxy-hexose. The possibility exists that 4-deoxy-D-arabinohexosyl side chains of 023-specific-polysaccharide disappeared as a result of a mutation of the parent strain. Although Citrobacter strain PCM 1487 contains 4-deoxy-D-arabinohexose and belongs to the chemotype CC-G, it cannot be included to the serotypes 04, 027 or 036. Instead, it represents a new serotype, with O-specific polysaccharide composed of 4-deoxy-D-arabinohexose, N-acetylglucosamine and N-acetylgalactosamine.