The O9 antigen of Burkholderia (Pseudomonas) cepacia has the following
disaccharide repeating-unit: --> 4)-alpha-D-Glcp-(1 --> 3)-alpha-L-Rh
ap-(1 --> The same unit is present in the O antigens of Serratia marce
scens strain S1254 and serogroup O4 (predominantly acetylated at O-2 o
f rhamnose in the latter case).