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 <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.