STRUCTURE OF THE PUTATIVE O-10 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 Acinetob acter baumannii serogroup 010. By means of NMR studies and chemical de gradations, the repeating unit of the polymer (the putative 010 antige n) was identified as a branched pentasaccharide of the structure shown . [GRAPHICS] at O-2 and O-4 with alpha-D-Gal p and beta-D-Gal p, respe ctively. The fractions differed in that one contained much more uronic acid than the other, with corresponding predominance of side chains c ontaining alpha-D-Glc p A-(1 --> 3)-D-Glc p, (alpha-D-Gal p-(1 -->, 2) -D-Glc p, and beta-D-Gal f units.