The capsular polysaccharides (K antigens) are linked to virulence in E. coli (Jann and Jann, 1987), and strains possessing the K1 antigen exhibit increased invasiveness and are associated with septicaemia and meningitis (Smith and Huggins, 1982; Silver and Vimr, 1990). This evidence concerns the gene KRT1 and infectious meningitis.