The urinary microbiota: a paradigm shift for bladder disorders?

Abstract

Purpose of Review A resident microbial community (the female urinary microbiota, FUM) exists within the female bladder of many adult women. Information about the FUM is likely to modify the diagnosis, prevention and treatment of adult women with urinary disorders. This review highlights key findings from recent literature relevant to adult, non-pregnant women. Recent Findings Similar to other human microbial communities, the FUM varies in its characteristics, including organism diversity and predominant organism identity. Recent literature reveals previously undetected organisms and community characteristics that appear associated with certain urinary symptoms, including urinary tract infection and urgency urinary incontinence. The role of individual organisms may range from beneficial to pathogenic, and may vary based on an individual’s FUM characteristics. The simple dichotomy of “infected” or “sterile” no longer sufficiently captures the microbiological complexity of the female bladder. Summary Deeper understanding of the FUM should yield better methods to restore the microbiota to a healthy state, providing symptom relief. Opportunities to modify the FUM without antibiotic use are exciting possibilities for future research; stand-alone antibiotic use may be re-evaluated to improve treatment precision. Long-standing nomenclature for conditions such as asymptomatic bacteriuria and urinary tract infection will likely require modification.

Urinary Tract Infection: Pathogenesis and Outlook

“…Finally, with regard to updated UTI therapeutics, one must consider an impending paradigm shift regarding the “normal” state of the bladder – which has long been assumed to be sterile [95]. Enhanced culture techniques, as well as metagenomics on catheter-collected samples, have detected urinary bacteria in healthy and asymptomatic women [96].…”

Sex differences in lower urinary tract biology and physiology

“…Other studies have revealed associations between bladder bacteria and post-operative and post-instrumentation UTIs [ 96 , 97 ], urgency urinary incontinence [ 98 , 99 ], and response to overactive bladder treatment [ 100 ]. These findings suggest that the urinary tract possesses its own protective microbiota and that disruption (dysbiosis) of this community results in LUT symptoms (for recent reviews, see [ 101 – 103 ]).…”

Diversity of the midstream urine microbiome in adults with chronic kidney disease

“…Although the vast majority of genitourinary bacteria, which includes bacteria from the urethra, vagina, vulva, and bladder, cannot be cultured by standard clinical microbiology urine culture methods [ 7 , 8 ], they can be identified using high throughput 16S rRNA sequencing or new enhanced urine culture techniques [ 2 , 4 , 8 – 10 ]. The presence of urinary bacteria does not indicate UTI, as the bacteria that comprise the resident urinary microbiome differ from those associated with clinical UTIs [ 5 , 6 , 11 , 12 ]. While few studies have examined the diversity of the urine microbiome, current evidence links microbial diversity in catheterized urine specimens with urgency urinary incontinence (UUI) and response to treatment for lower urinary tract symptoms, especially those associated with UUI [ 13 , 14 ].…”