Urinary tract infection in infants: use of urine specimens obtained by suprapubic bladder aspiration in order to determine the reliability of culture specimen of urine collected in perineal bag

Objective: To determine if culture specimens of urine collected in perineal bags is reliable in detecting urinary tract infections in infants.

Methods: A prospective study was carried out in a pediatric emergency room of an urban teaching hospital. Forty-eight infants, 12 months old or less, requiring an uncontaminated urine specimen due to the evaluation of febrile illness, suspected urinary tract infection or to a previously contaminated urine culture specimen. Two consecutive urine specimens were collected for culture. A urine specimen was collected in a perineal bag and afterwards all patients underwent suprapubic bladder aspiration. Cultures were considered positive if pure growth of more than 1.000 colonies/ml developed in the suprapubic aspiration urine specimen.

Results: Thirty-two infants had coincident cultures in both urine specimens. A positive culture specimen of urine collected in a perineal bag (pure growth of more than 100,000 colonies/ml) had high sensitivity (100%) and high specificity 88.6% in predicting positive cultures from urine obtained by suprapubic aspiration.

Conclusions: A urine culture specimen meticulously collected with a perineal bag is a good screening method for detecting urinary tract infection in low risk infants.