Ampicillin and pivampicillin in the treatment of urinary tract infection in children.

16 children, aged 1-10 years, suffering from urinary tract infection were randomly divided into two groups. Ten children were treated with ampicillin pediatric suspension in a dose of 100 mg ampicillin/kg/24 hours divided in 4 doses, and 6 children with pivampicillin base pediatric suspension in a dose of 64.8 mg/kg/24 hours divided in 4 doses (approximately 50 mg ampicillin/kg). The treatment period was 14 days with all infections being cured. Despite the fact that pivampicillin was administered in half of the dosage of ampicillin the resulting peak serum concentration was 65% higher and was achieved more rapidly. The bioavailability and urine concentration were also greater. A marked change in the rectal aerobic bacterial flora occurred during both treatment regimens. In 13 children (81%) a shift took place from ampicillin-sensitive E. coli to ampicillin-resistant Klebsiella strains as the predominating microbe, equally often in both groups of treatment. Ampicillin-resistant E. coli appeared in one child in each group.