The urinary microbiome after paediatric bladder augmentation: a scoping review with comparative insights from adult urinary diversion surgeries.

Bladder augmentation is a lifelong reconstructive procedure for children with severe lower urinary tract dysfunction, but recurrent urinary tract infection, urolithiasis and mucus-related complications remain incompletely understood. This scoping review mapped evidence on the urinary microbiome after paediatric bladder augmentation and assessed transferable insights from adult bowel-derived urinary diversion. A PRISMA-ScR-guided search of PubMed, Embase and Web of Science identified peer-reviewed studies and conference abstracts published from January 2016 to April 2026 that used culture-independent sequencing. Seven studies were included: two paediatric and five adult, comprising three cross-sectional studies, two reports from one prospective cohort and two case reports. Paediatric studies reported contrasting enteric-dominant and native-bladder-like communities, with no consistent clinical associations. Adult studies more consistently suggested time-dependent restructuring, reservoir-specific microbial patterns and fungal involvement, although associations with urinary tract infection remained inconsistent. The paediatric evidence is insufficient to define microbiome composition, temporal behaviour or clinical significance after augmentation. Adult findings primarily provide a methodological template for future prospective, longitudinal, within-patient paediatric studies incorporating standardised urine and mucosal sampling, bacterial and fungal sequencing, metabolomics and predefined clinical outcomes.