Natural history of bacteriuria in schoolgirls. A long-term case-control study.

To define better the natural history of bacteriuria in females, we followed 60 schoolgirls with bacteriuria and 38 matched controls for periods ranging from nine to 18 years. Among the schoolgirls with bacteriuria (greater than or equal to 10(5) organisms per milliliter in two or more consecutive cultures), reflux was repaired in five, nephrectomy was performed in two, and reduced inulin clearance was noted in one subject with atrophic pyelonephritis. Serum creatinine was slightly higher in cases than in controls. Renal scars or caliectasis occurred in 16 cases but in none of the controls. Blood pressure was similar in both groups. Episodes of bacteriuria in cases and controls were, respectively: five or more episodes, 21.7 and 2.6 per cent; and episodes during pregnancy, 63.8 and 26.7 per cent. Seven children of the cases but none of the children of controls showed urinary-tract infections. Bacteriuria among schoolgirls defines a group at great risk of recurrent symptomatic infections and renal scars and at low risk of reduced renal function.