The number of women with at least 1 pelvic floor disorder (e.g. urinary incontinence (UI) or pelvic organ prolapse (POP) is predicted to increase from 28.1 million in 2010 to 43.8 million in 2050. During this period, the number of women with UI will increase 55% from 18.3 million to 28.4 million and the number of women with POP will increase 46% from 3.3 to 4.9 million. Unfortunately for these women, the causes of UI, POP and other lower pelvic disorders remain unknown.
We propose a novel hypothesis - the normal urinary tract is colonized by bacteria and that perturbations in the normal pattern of colonization either cause or influence the progression of certain lower pelvic disorders. This hypothesis is novel, primarily because the urinary tract has long been considered sterile. While urine cultures have been the gold standard for assessment of bacteria in the urinary tract, evidence exists that urine may not be sterile & that certain clinical conditions of the lower urinary tract may result from an imbalance in the composition of the bacteria that normally colonize the lower urinary tract. First, culture-dependent techniques cannot rule out bacterial colonization because the vast majority of bacteria cannot be cultured. Second, the few investigators who have used culture-dependent microbial identification methods to survey the male urogenital tract have found substantial microbial diversity. Third, a recent comprehensive culture-independent survey of the male urogenital tract has revealed a plethora of fastidious & uncultivated bacteria. These studies support the hypothesis that normal male urine is NOT sterile. Whether normal female urine is sterile remains unknown. How non-cultivated organisms relate to human health and disease also remains largely unknown, but it is likely that many such organisms will prove to be important as our ability to identify them develops. Fortunately, advances in culture-independent methods make it possible to identify non-cultivated organisms.
We plan to use one of these culture-independent methods, 16S rRNA pyrosequencing, to survey urine samples taken from POP/UI patients and normal controls. Our preliminary results suggest (1) that the urine of POP/UI patients is generally not sterile; (2) that these bacterial communities are diverse; (3) that the composition often differs between patients; and (4) that different parts of the lower urinary tract are colonized by distinctly different communities of bacteria. These results also suggest the possibility that the female urinary tract can become colonized by normal and abnormal vaginal flora.