Structure of the O2 antigen of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia

An O antigenic polymer containing l-rhamnose, d-mannose, and l-xylose was isolated from the lipopolysaccharide present in the reference strain for Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia serogroup O2, by mild acid hydrolysis and gel-permeation chromatography. By means of NMR spectroscopy and chemical degradations, the polysaccharide was found to be based on a branched trisaccharide repeating-unit of the structure shown.