Identification of a carbohydrate receptor recognized by uropathogenic Escherichia coli

Earlier investigations have shown that pyelonephritic Escherichia coli specifically recognize and bind to carbohydrate structures correlated to the P blood group antigens. These findings are confirmed and extended in this study. Twenty-two of 23 nonselected E. coli strains from children with acute febrile pyelonephritis failed to agglutinate human erythrocytes lacking the antigens within the P blood group system. Only one of 32 faecal isolates exhibited this specific agglutinating property. The new informatin in this paper is that P2k erythrocytes, containing only the Pk antigen, were agglutinated to the same extent by pyelonephritic E. coli strains, giving further support to the proposal that the Pk glycosphingolipid is related to the receptor for pyelonephritic E. coli. In addition, the importance of the oligosaccharide moiety of the Pk glycosphingolipid for the binding of E. coli was further investigated. The synthesized disaccharide alpha-D-Galp-(1-4)-beta-D-Galp-1-O-0-NO2 inhibited the agglutination of human erythrocytes caused by two pyelonephritic E. coli strains at concentrations of less than 1 mM. Hence, the minimal receptor structure recognized by these E. coli strains appears to be the alpha-D-Galp-(1-4)-beta-D-Galp structure. How generally valid this observation may be needs further investigation. The findings may open new possibilities for diagnosis and treatment of urinary tract infection.