E. coli cause greater than 90% of urinary tract infections (UTI) in childhood. The capacity to adhere to urinary tract epithelial cells characterizes E. coli strains that cause acute pyelonephritis. Galactose alpha 1-4Galactose beta is the minimal receptor for adhering uropathogenic E. coli. Gal alpha 1-4Gal beta-binding bacteria caused significantly higher body temperature, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), pyuria, and lower renal concentrating capacity than E. coli lacking this specificity. The binding bacteria thus appeared to be more potent inducers of acute inflammation. Since inflammation may lead to tissue damage, we examined the relationship of infection with Gal alpha 1-4Gal beta-positive bacteria to renal scarring. The frequency of renal scarring was 5% in boys with Gal alpha 1-4Gal beta-positive and 40% in boys with Gal alpha 1-4Gal beta-negative E. coli. Analysis of binding capacity with the help of a newly developed latex agglutination assay can thus be used as an effective predictor of risk for renal scarring.