Analysis of Uropathogens of Febrile Urinary Tract Infection in Infant and Relationship with Vesicoureteral Reflux

Purpose: This study aimed to investigate the relationship between uropathogens of infants with febrile urinary tract infection (UTI) and vesicoureteral reflux (VUR). Materials and Methods: We analyzed 308 infants hospitalized for febrile UTI between January 2010 and December 2015, and assessed the voiding cystourethrography (VCUG). The medical records, including clinical symptoms, laboratory findings, urinalysis, urine culture tests, ultrasound (US), dimercaptosuccinic acid scan, and VCUG, were retrospectively obtained. The incidences of VUR and high-grade VURs (III, IV, and V) were analyzed in 4 groups categorized by uropathogens and renal US findings. Results: The mean age of 308 infants was 3.29±2.18 months. The male-to-female ratio was 3.46:1. In urine culture tests, 267 infants (86.69%) showed single bacterial uropathogen; Escherichia coli in 241 infants (78.25%) and non-E. coli uropathogens in 26 infants (8.44%). Multiple distinctive microorganisms were identified as causative uropathogens in 41 infants (13.31%). Abnormal findings of US and VCUG were identified in 216 and 64 patients, respectively. In 308 infants, the incidences of VUR and high-grade VUR were not different among the 4 groups. In 239 male infants, the incidences of high-grade VUR were higher in patients with non-E. coli single or multiple uropathogen and with abnormal US findings (p=0.042). Conclusions: In male infants with non-E. coli uropathogen or multiple uropathogens and with abnormal US findings at febrile UTI, there was an increased chance of finding high-grade VURs on subsequent VCUG tests.