Spontaneous Clearance of Asymptomatic Bacteriuria in Infants

Abstract

In an unselected population of 3,581 infants, 14 girls and 36 boys were found to have bacteriuria verified by suprapubic aspiration. Among the bacteriuric infants, one girl and one boy developed symptoms of pyelonephritis close to the time of detection; the others remained asymptomatic. Eleven girls and 34 boys were left untreated. One of these girls and 7 of the boys became abacteriuric after treatment for respiratory tract infections. Ten girls and 26 boys became spontaneously abacteriuric, with a median persistence of bacteriuria of 2 months in girls and 1.5 months in boys. Recurrences were observed among boys only in those who had been treated with antibiotics.

Diagnostic Accuracy of the Urinalysis for Urinary Tract Infection in Infants <3 Months of Age

“…Wettergren et al 8,9 performed screening bag urine cultures on 3581 asymptomatic infants at 3 separate intervals during the first year of life, beginning at 0.25 to 2 months. Infants with $50 000 CFU/mL from 2 successive bag cultures underwent suprapubic aspiration.…”

“…Only 2 of the 45 untreated infants were diagnosed with pyelonephritis within 2 weeks of detection of the bacteriuria. 9 Follow-up tests for renalconcentrating capacity (a measure of renal function) were done in 47 of 50 children and were normal. 8 In a study by Hoberman et al, 7 of 212 children ,2 years of age with positive urine cultures (.50 000 CFU/mL), 22 patients had ,10 WBC/mm 3 from an enhanced UA (equivalent to ∼2 WBC/ HPF from an automated UA 19 ).…”

“…However, the findings of a positive urine culture in a patient with a negative UA also may reflect a false-positive urine culture due to asymptomatic bacteriuria or contamination. [7][8][9][10] The 2011 American Academy of Pediatrics' (AAP) UTI guideline suggests that the diagnosis of UTI should require an abnormal UA in addition to a positive urine culture. 4 However, these guidelines do not include infants ,2 months, and young infants with a negative UA and a positive urine culture are generally considered to have UTI.…”

Difficulties in diagnosing urinary tract infections in small children

“…All infants had bag urine cultures performed at 2 weeks, 3 months and 10 months of age. Positive cultures were always confirmed with a culture of urine collected by a supra-pubic bladder puncture [14].…”

“…In the same cohort of children, another 1.2% of the boys and 1.1% of the girls developed an episode of febrile symptomatic UTI. Follow-up studies showed that the ABU lasted between 0.5 and 7.5 months (median of 2 and 1.5 months for the girls and boys, respectively) and had resolved spontaneously without any signs of kidney scarring by the 6-year follow-up [14][15][16]. A subsequent Turkish study which only used clean catch cultures, without confirmation on urine collected by SPA, showed a prevalence of bacteriuria in 4% of newborns and 5.2% of infants [17].…”