Urinary Microbiome in Bladder Diseases-Review

Urobiome of patients with diabetic kidney disease in different stages is revealed by 2bRAD-M

BACKGROUND

Knowledge of the urinary microbiome (urobiome) in diabetic kidney disease (DKD) remains limited. The most commonly used 16S rRNA sequencing technique can only provide bacterial identification at the genus level. As a novel technique, 2bRAD sequencing for microbiome (2bRAD-M) can be used to identify the low-biomass microbiome at the species level. In this study, we used 2bRAD-M to compare the urobiome composition of patients with DKD at different stages with healthy individuals and those with type 2 diabetes mellitus (T2DM), with the expectation that we would find discriminative species correlated with DKD.

METHOD

Healthy controls, patients with DKD with microalbuminuria (DKD1 group) or macroalbuminuria (DKD2 group), and patients with T2DM were recruited (n = 20 for each group). The first-morning urine was collected for 2bRAD-M testing. The albumin-to-creatinine ratio (ACR) was also measured with urine samples. Serum samples were collected for detecting clinical indicators. The microbial diversity and composition based on abundance were calculated. Differential bacteria for different groups were identified. Besides, the correlation between discriminative bacteria and clinical indices was also analyzed.

RESULTS

Urobiome diversity was significantly reduced in the DKD groups. In the DKD1 group, was the dominant genus, followed by Pseudomonas_E, whereas in the DKD2 group, Pseudomonas_E became the dominant genus and Escherichia was notably reduced. Both Bifidobacterium and Streptococcus, which were the top genera in the control group, were substantially decreased in the DKD groups. The discriminative species for DKD1 included Escherichia coli and Acinetobacter johnsonii, while for DKD2, Pseudomonas_E oleovorans, Enterococcus faecalis, and Morganella morganii were identified. Pseudomonas_E, Enterococcus and Morganella showed a strong correlation with renal function indicators and urinary protein levels.

CONCLUSION

The urobiome diversity and composition in patients with DKD were markedly different from those in healthy individuals and T2DM patients. These findings provide valuable insights into the onset and progression of DKD, driven by changes in the urinary bacterial community structure.

The Role of Urinary Microbiome Analysis in the Diagnostic Approach and Management of Urinary Incontinence: A Systematic Review

Urinary incontinence (UI) is a significant global health issue that impacts mainly middle-aged women, severely affecting their quality of life. Emerging research highlights the urinary microbiome's complex role in the etiology and management of UI, with microbial dysbiosis potentially influencing symptom severity and treatment outcomes. This systematic review aimed to evaluate the current evidence on the urinary microbiome's role in diagnosing and managing UI, focusing on variations in microbial composition across UI subtypes. We identified 21 studies, mostly employing 16S rRNA sequencing to characterize urinary microbiota and their associations with various UI subtypes, including urgency urinary incontinence (UUI), overactive bladder (OAB), and stress urinary incontinence (SUI). The findings revealed distinct microbial patterns, such as reduced Lactobacillus levels and increased Gardnerella prevalence, particularly in UUI. Altered microbiome profiles correlated with symptom severity, with reduced Lactobacilli suggesting a protective role in maintaining urinary health. Specific microbial species, including Actinotignum schaalii and Aerococcus urinae, emerged as potential biomarkers for UI diagnosis. Despite promising findings, limitations such as small sample sizes, variability in microbiome profiling methods, and insufficient causal evidence underscore the need for further research.

Lower Urinary Tract Inflammation and Infection: Key Microbiological and Immunological Aspects

The urinary system, primarily responsible for the filtration of blood and waste, is affected by several infectious and inflammatory conditions. Focusing on the lower tract, this review outlines the physiological and immune landscape of the urethra and bladder, addressing key immunological and microbiological aspects of important infectious/inflammatory conditions. The conditions addressed include urethritis, interstitial cystitis/bladder pain syndrome, urinary tract infections, and urosepsis. Key aspects of each condition are addressed, including epidemiology, pathophysiology, and clinical considerations. Finally, therapeutic options are outlined, highlighting gaps in the knowledge and novel therapeutic approaches.