Jung Won Lee
Urinary tract infections (UTIs) are among the most common bacterial infections in infants and a significant cause of antibiotic exposure. Recent advances in culture-independent sequencing and improved urine culture techniques have revealed that urine contains resident microbial communities, collectively known as the urinary microbiome (urobiome). Additionally, emerging evidence supports the existence of a gut-bladder axis, where intestinal dysbiosis may lead to uropathogen colonization, immune modulation, and UTI recurrence. This review summarizes current pediatric research connecting alterations in the urinary and gut microbiomes to UTI susceptibility, recurrence, and clinical outcomes, specifically in infants. We also address the unique methodological challenges in pediatric urobiome research and outline future directions for applying microbiome and metabolomics insights to clinical practice.