Pediatric urinary tract infections and vesicoureteral reflux: from traditional concepts to individualized and risk-based management

Urinary tract infections (UTIs) are among the most frequent bacterial infections in childhood and remain a major cause of antibiotic exposure, diagnostic imaging and medical consultation. However, the clinical framework within which pediatric UTIs are evaluated has changed substantially. Historical studies established a close relationship between febrile UTI, vesicoureteral reflux (VUR), renal scarring and subsequent chronic kidney disease. Contemporary evidence indicates that this paradigm overestimated the contribution of infection to long-term kidney damage and often failed to distinguish acquired scars from congenital kidney hypodysplasia. The current challenge is therefore to identify the minority of children at genuine risk while avoiding unnecessary investigations and prolonged antimicrobial treatment in the majority. Susceptibility to UTI results from interactions among bacterial virulence, urinary tract anatomy, bladder and bowel function, genetic background, innate immunity and the urinary microbiome. Uromodulin, antimicrobial peptides and the resident urinary microbiome may contribute to protection against infection and could provide future biomarkers or therapeutic targets. The management of acute febrile UTI has progressively become less invasive. In clinically stable children, oral antibiotics are as effective as intravenous treatment, and emerging evidence supports shorter or response-adapted courses rather than the traditional 10–14 days of therapy. Although shorter treatment reduces antibiotic exposure and adverse effects, its potential association with a modest increase in early recurrence requires careful patient selection. The role of adjunctive corticosteroids in preventing renal scarring remains uncertain. Available trials suggest a possible benefit, but the evidence is insufficient to support routine administration after a first febrile UTI. Their use might eventually be considered in selected children with pre-existing kidney abnormalities, recurrent pyelonephritis, previous scars or kidney transplantation. Prevention should similarly be individualised. Continuous antibiotic prophylaxis provides only a modest absolute benefit in children with low-grade VUR, whereas the PREDICT trial demonstrated a significant reduction in recurrent UTI among infants with predominantly high-grade VUR. Nevertheless, prophylaxis has not yet shown a clear benefit for long-term kidney function and may adversely affect gut microbial maturation, beneficial bacterial populations and microbial metabolism. These findings support limiting prophylaxis to children whose anatomical and clinical risk justifies prolonged antibiotic exposure. The management of pediatric UTI is therefore moving from a uniform, reflux-centred approach towards individualised risk stratification. Appropriate care should combine effective but shorter acute treatment, selective use of imaging and prophylaxis, attention to modifiable risk factors, and preservation of the urinary and intestinal microbiomes. Future studies must determine whether these less aggressive strategies can reduce treatment burden and antimicrobial resistance without compromising the prevention of recurrent infection and long-term kidney injury.