Urinary shedding of common DNA viruses and their possible association with bladder cancer: a qPCR-based study.

After a decade of human urinary microbiota research, little is known about the composition of the urinary virome and its association with health and disease. This study aimed to investigate the presence of 10 common DNA viruses in human urine and their putative association with bladder cancer (BC). Catheterized urine samples were collected from patients undergoing endoscopic urological procedures under anesthesia. After DNA extraction from the samples, viral DNA sequences were detected using real-time PCR. Viruria rates were compared between BC patients and controls. A total of 106 patients (89 males and 17 females) were included in the study. Fifty-seven (53.8%) were BC patients and 49 (46.2%) had upper urinary tract stones or bladder outlet obstruction. The viruses detected in the urine were human cytomegalovirus (2.0%), Epstein-Barr virus (6.0%), human herpesvirus-6 (12.5%), human papillomavirus (15.2%), BK polyomavirus (15.5%), torque teno virus (44.2%), and JC polyomavirus (47.6%), while no adenoviruses, herpes simplex virus 1 and 2, or parvoviruses were found. There were statistically significant differences in HPV viruria rates between cancer patients and controls (24.5% vs. 4.3%, p=0.032 after adjustment for age and gender). Viruria rates increased from benign to non-muscle-invasive and muscle-invasive tumors. Patients with a history of BC have higher HPV viruria rates than controls. Whether this relationship is a causal one remains to be established by further research.

Bladder cancer is associated with decreased urinary microbiota diversity and alterations in microbial community composition.

INTRODUCTION: Human urine microbiota (UM) research has uncovered associations between composition of microbial communities of the lower urinary tract and various disease states including several reports on the putative link between UM and bladder cancer (BC). The aim of this study was to investigate male UM in patients with BC and controls using catheterised urine specimens unlike in previous studies. METHODS: Urine samples were obtained in theatre after surgical prepping and draping using aseptic catheterisation. DNA was extracted and hypervariable region V4 of the 16S rRNA gene was amplified using 515F and 806R primers. Sequencing was performed on Illumina MiSeq platform. Sequencing data were processed using appropriate software tools. Alpha diversity measures were calculated and compared between groups. Prevalence Interval for Microbiome Evaluation was used to test differences in beta diversity. RESULTS: A total of 63 samples were included in the analysis. Mean age of study subjects was 65.1 years (SD 12.5). Thirty-four men had bladder cancer and 29 participants were undergoing interventions for benign conditions (benign prostate hyperplasia or upper urinary tract stone disease). BC patients had lower UM richness and diversity than controls (83 vs. 139 operational taxonomic units, P = 0.015; Shannon index: 2.46 vs. 2.94, P = 0.049). There were specific taxa enriched in cancer (Veillonella, Varibaculum, Methylobacterium-Methylorubrum) and control groups (Pasteurella, Corynebacterium, Acinetobacter), respectively. CONCLUSION: BC patients had lower bladder microbiota richness and diversity than controls. Specific genera were enriched in cancer and control groups, respectively. These results corroborate some of previous reports while contradicting others. Future microbiota research would benefit from parallel transcriptomic/metabolomic analysis.

Bladder Microbiota Are Associated with Clinical Conditions That Extend beyond the Urinary Tract.

BACKGROUND: Since the discovery of the human urinary microbiota (UM), alterations in microbial community composition have been associated with various genitourinary conditions. The aim of this exploratory study was to examine possible associations of UM with clinical conditions beyond the urinary tract and to test some of the conclusions from previous studies on UM. METHODS: Catheterised urine samples from 87 men were collected prior to endoscopic urological interventions under anaesthesia. The composition of the bacterial community in urine was characterized using the hypervariable V4 region of the 16S rRNA gene. Samples from 58 patients yielded a sufficient amount of bacterial DNA for analysis. Alpha diversity measures (number of operational taxonomic units, ACE, iChao2, Shannon and Simpson indices) were compared with the Kruskal-Wallis test. Beta diversity (differences in microbial community composition) was assessed using non-metric dimensional scaling in combination with the Prevalence in Microbiome Analysis algorithm. RESULTS: Differences in bacterial richness and diversity were observed for the following variables: age, diabetes mellitus, dyslipidemia, smoking status and single-dose preoperative antibiotics. Differences in microbial community composition were observed in the presence of chronic kidney disease, lower urinary tract symptoms and antibiotic prophylaxis. CONCLUSIONS: UM appears to be associated with certain clinical conditions, including those unrelated to the urinary tract. Further investigation is needed before conclusions can be drawn for diagnostics and treatment.

Alpha-diversity and microbial community structure of the male urinary microbiota depend on urine sampling method.

Considerable variation exists in the methodology of urinary microbiota studies published so far including the cornerstone of any biomedical analysis: sample collection. The aim of this study was to compare the urinary microbiota of first-catch voided urine (FCU), mid-stream voided urine (MSU) and aseptically catheterised urine in men and define the most suitable urine sampling method. Forty-nine men (mean age 71.3 years) undergoing endoscopic urological procedures were enrolled in the study. Each of them contributed three samples: first-catch urine (FCU), mid-stream urine (MSU) and a catheterised urine sample. The samples were subjected to next-generation sequencing (NGS, n = 35) and expanded quantitative urine culture (EQUC, n = 31). Using NGS, Bacteroidetes, Firmicutes, and Proteobacteria were the most abundant phyla in our population. The most abundant genera (in order of relative abundance) included: Prevotella, Veillonella, Streptococcus, Porphyromonas, Campylobacter, Pseudomonas, Staphylococcus, Ezakiella, Escherichia and Dialister. Eighty-two of 105 samples were dominated by a single genus. FCU, MSU and catheterised urine samples differed significantly in three of five alpha-diversity measures (ANOVA, p < 0.05): estimated number of operational taxonomic units, Chao1 and abundance-based coverage estimators. Beta-diversity comparisons using the PIME method (Prevalence Interval for Microbiome Evaluation) resulted in clustering of urine samples according to the mode of sampling. EQUC detected cultivable bacteria in 30/31 (97%) FCU and 27/31 (87%) MSU samples. Only 4/31 (13%) of catheterised urine samples showed bacterial growth. Urine samples obtained by transurethral catheterisation under aseptic conditions seem to differ from spontaneously voided urine samples. Whether the added value of a more exact reflection of the bladder microbiota free from urethral contamination outweighs the invasiveness of urethral catheterisation remains to be determined.