Structure of the putative O10 antigen from Acinetobacter baumannii

A polysaccharide containing l-rhamnose, 2-acetamido-2-deoxy-d-glucose, and 2-acetamido-2-deoxy-d-mannose was obtained from an aqueous phenol extract of isolated cell walls from the reference strain for Acinetobacter baumannii serogroup O10. By means of NMR studies and chemical degradations, the repeating unit of the polymer (the putative O10 antigen) was identified as a branched pentasaccharide of the structure shown.