Probiotic prophylaxis in adult women with recurrent uncomplicated urinary tract infections: A systematic review of randomized controlled trials.

INTRODUCTION

Recurrent urinary tract infection (rUTI) in women represents a common clinical problem whose traditional management through continuous antibiotic prophylaxis contributes to the development of antimicrobial resistance. Probiotics, particularly Lactobacillus strains, have emerged as a potentially effective non-antibiotic alternative by restoring the urogenital microbiota.

METHODS

A systematic review was conducted following PRISMA guidelines. Randomised controlled trials evaluating the efficacy and safety of probiotic prophylaxis, administered orally or intravaginally, in adult women with rUTI, compared to placebo or antibiotic prophylaxis, were included. MEDLINE, EMBASE, CENTRAL, LILACS and Google Scholar were searched up to December 2025. Risk of bias was assessed using RoB 2, and the certainty of evidence with GRADE. Due to clinical heterogeneity, a narrative synthesis was performed.

RESULTS

Four randomised controlled trials (n = 616) were included. Compared with placebo, probiotics were associated with a reduction in the recurrence of urinary tract infections and an increase in the time to first recurrence. The most precise effect estimate available was a relative risk of 0.50 (95% CI: 0.20-1.20) for intravaginal Lactobacillus crispatus, with a recurrence rate of 15% versus 27% in the placebo group. Intravaginal administration showed a consistent trend toward greater clinical benefit across all studies, associated with effective vaginal recolonisation. No serious adverse events were reported.

CONCLUSIONS

Probiotic prophylaxis is a promising and apparently safe strategy for preventing rUTI in adult women. Intravaginal administration appears to offer the greatest clinical benefit and could be a valuable non-antibiotic alternative for reducing the pressure for antimicrobial resistance.