mutants of a virulent 018 : k1 e. coli strain defective in the synthesis of the capsular polysaccharide or the o-antigen of lipopolysaccharide were avirulent as were 01 : k1 bacteria , which are under-represented among e. coli isolates from neonatal meningitis .
C0069180
o-antigen
C0023810
lipopolysaccharide