Antibody-coated bacteria in the urine of infants and children with their first two urinary tract infections.

The presence of antibody-coated bacteria in urine has been shown to be an indicator for renal bacteriuria in adults with chronic UTI. To evaluate this method (ABCU test) in pediatric patients, 128 infants and children with their first UTI were investigated. Twenty-nine patients of the 78 who had a first clinically defined upper UTI had antibody-coated bacteria in urine. The test was seldom (2/20) positive in the infants under six months. In the older patients (27/58 ABCU-positive) the frequency of positive tests increased with the duration of symptoms. When the symptoms had lasted for over one weeks, 11 out of the 13 children with their first upper UTI showed antibody-coated bacteria in urine. Four of the 36 first lower UTIs and 5 out of the 14 asymptomatic cases were ABCU-positive. The patients were followed-up for an average of 9 months. Those who were classified as having first upper UTI had in most cases a positive ABCU test in recurrences, independently of the clinical picture. The recurrences after the first lower UTIs showed antibody-coated bacteria in urine only when the recurrence was classified as upper UTI on the grounds of the clinical criteria used.