PT - JOURNAL ARTICLE AU - Jean-Yves Pauchard AU - Hassib Chehade AU - Chafika Zohra Kies AU - Eric Girardin AU - Francois Cachat AU - Mario Gehri TI - Avoidance of voiding cystourethrography in infants younger than 3 months with <em>Escherichia coli</em> urinary tract infection and normal renal ultrasound AID - 10.1136/archdischild-2016-311587 DP - 2017 Apr 13 TA - Archives of Disease in Childhood PG - archdischild-2016-311587 4099 - http://adc.bmj.com/content/early/2017/04/13/archdischild-2016-311587.short 4100 - http://adc.bmj.com/content/early/2017/04/13/archdischild-2016-311587.full AB - Background and objective Urinary tract infection (UTI) represents the most common bacterial infection in infants, and its prevalence increases with the presence of high-grade vesicoureteral reflux (VUR). However, voiding cystourethrography (VCUG) is invasive, and its indication in infants &lt;3 months is not yet defined. This study aims to investigate, in infants aged 0–3 months, if the presence of Escherichia coli versus non-E. coli bacteria and/or normal or abnormal renal ultrasound (US) could avoid the use of VCUG.Method One hundred and twenty-two infants with a first febrile UTI were enrolled. High-grade VUR was defined by the presence of VUR grade ≥III. The presence of high-grade VUR was recorded using VCUG, and correlated with the presence of E. coli/non-E. coli UTI and with the presence of normal/abnormal renal US. The Bayes theorem was used to calculate pretest and post-test probability.Results The probability of high-grade VUR was 3% in the presence of urinary E. coli infection. Adding a normal renal US finding decreased this probability to 1%. However, in the presence of non-E. coli bacteria, the probability of high-grade VUR was 26%, and adding an abnormal US finding increased further this probability to 55%.Conclusions In infants aged 0–3 months with a first febrile UTI, the presence of E. coli and normal renal US findings allow to safely avoid VCUG. Performing VCUG only in infants with UTI secondary to non-E. coli bacteria and/or abnormal US would save many unnecessary invasive procedures, limit radiation exposure, with a very low risk (&lt;1%) of missing a high-grade VUR.