Bladder Microbiome in the Context of Urological Disorders—Is There a Biomarker Potential for Interstitial Cystitis?

Since the development of modern cultivation and sequencing techniques, the human microbiome has increasingly become the focus of scientific attention. Even in the bladder, long considered to be a sterile niche, a highly variable and complex microbial colonization has now been demonstrated. Especially in the context of diseases such as interstitial cystitis, whose etiopathogenesis is largely unknown, and whose diagnosis is based on a process of exclusion of confusable diseases, science hopes to gain far-reaching insights for etiology and diagnosis, including the identification of potential biomarkers. While for functional disorders such as urge urinary incontinence and overactive bladder syndrome, initial associations have been demonstrated between reduced microbial diversity and increased symptomatology, as well as shifts in the abundance of specific microorganisms such as Lactobacillus or Proteus, studies in interstitial cystitis show conflicting results and have failed to identify a putative organism or urotype that clearly distinguishes the urinary microbiome of patients with IC/BPS from that of healthy controls. At the present time, therefore, the new insights into the bladder microbiome and its potential influence on urologic disease cannot yet be used in the context of elucidating possible etiopathogenetic causes, as well as in the use of a biomarker for diagnostic or prognostic purposes. Further studies should focus primarily on uniform procedures and detection methods to achieve better comparability of results and increase the likelihood of detecting hidden patterns.