Asymptomatic bacteriuria in school girls. V. The clinical course and response to treatment.

The short-term prognosis of 116 school girls with asymptomatic bacteriuria (ABU) treated or left untreated is reported. In untreated girls a spontaneous remission was obtained in 11% within one year. A short course of nitrofurantoin eliminated the bacteriuria in 93% of the girls in the treatment group. The recurrence rate was 30% in one year in the patients that became abacteriuric spontaneously, after a bladder washout test or after treatment with penicillin or nitrofurantoin. The first recurrence occurred withn 3 months in 79% (19/24). Nineteen of the 24 patients with recurrences (79%) had a third infection within 9 months. In patients with parenchymal reduction or reflux the renal concentrating capacity increased significantly after treatment of the bacteriuria. All the girls left untreated had normal renal concentrating capacity on detection and this remained unchanged during the year of follow-up. One of 28 untreated girls attracted a symptomatic pyelonephritis caused by a strain different from that at detection of ABU. Of 81 girls cured from the bacteriuria 24 recurred, 5 with a symptomatic pyelonephritis and 3 with cystitis. It is concluded that strains isolated from girls with ABU do not commonly cause symptomatic pyelonephritis.