Localization and therapy of urinary tract infections of childhood.

One hundred four patients with 124 episodes of urinary tract infection were studied. Serum C-reactive protein (CRP) was determined on diagnosis of each patient. Children with a CRP equal to or greater than 30 micrograms/ml (CRP-pos) differed significantly from those with values less than 30 micrograms/ml (CRP-neg) in age, clinical presentation, K type of Escherichia coli causing disease, frequency or radiographic abnormalities, and presence of antibody coating of bacteria in the urinary sediment. E. coli K1 strains caused disease significantly more often in CRP-pos than in CRP-neg patients, and children with K1 infections were younger than those with non-K1 infections. The antibody-coated bacteria test was neither sensitive nor specific for localization of infection in pediatric patients. Determination of K1 antibody concentrations in serum and urine of E. coli K1-infected children provided data supporting the measurement of CRP as one means of localizing urinary tract infections. Patients with CRP-neg infections were treated as successfully with four days of antimicrobial therapy as with ten days.