Introduction and objective:
Urinary incontinence (UI) is defined as any involuntary leakage of urine and may affect up to half of women, depending on the population and methodology used. Consequently, there is an ongoing need for objective markers that could improve phenotyping of women with lower urinary tract symptoms (LUTS) and support more targeted management. A major conceptual shift occurred after the demonstration that urine is not sterile. Using culture-independent methods (16S rRNA sequencing) and enhanced quantitative urine culture (EQUC), resident microbial communities have been identified in the female bladder.

Review methods:
The aim of the scoping review is to map and summarize evidence from 2012–2024 on the relationship between the urinary microbiome and female UI, with particular emphasis on differences reported between UI subtypes (SUI, UUI/OAB, and MUI), and to identify key gaps in knowledge, and methodological challenges relevant to future diagnostic and therapeutic research.

Brief description of the state of knowledge:
Pearce et al. compared catheterized urine from women with and without UUI symptoms using both 16S rRNA sequencing and EQUC. They reported lower overall abundance of Lactobacillus in the UUI group, with enrichment of genera including Gardnerella, and differences in Lactobacillus species distribution (e.g., L. gasseri more frequent in UUI vs. L. crispatus more frequent in controls).

Summary:
Evidence accumulated over the last 12 years confirms that urine in healthy women is not sterile and that urgency-predominant phenotypes (OAB/UUI) most consistently differ from asymptomatic controls in the structure of the urinary microbiome community. Reported patterns most often include reduced Lactobacillus dominance and/or increased prevalence of genera such as Gardnerella, Aerococcus, Proteus, or Enterobacteriaceae.