Does the urinary microbiome profile change after treatment of bladder cancer?

Introduction We sought to investigate the change in the urinary microbiome profile after transurethral resection of bladder tumor (TURBT). Methods Urine specimens were collected from consecutive patients with bladder cancer. Patients were divided into those with bladder tumors (“Tumor group”: de novo tumors or recurrent/progressed after TURBT ± intravesical therapy) versus those without evidence of recurrence after treatment “No Recurrent Tumor group”. Samples were analyzed using 16S rRNA sequencing. Alteration in the urinary microbiome was described in terms of alpha (diversity within a sample measured by Observed, Chao, Shannon, and Simpson indices), beta diversities (diversity among different samples measured by Brady Curtis Diversity index), and differential abundance of bacteria at the genus level. Analyses were adjusted for gender, method of preservation (frozen vs preservative), and method of collection (mid-stream vs. catheter). Results Sixty-eight samples were analyzed (42 in “Tumor” vs 26 in “No Recurrent Tumor” groups). The median age was 70 years (IQR 64–74) and 85% were males. All patients in the “No Recurrent Tumor” group had non-muscle invasive bladder cancer and 85% received BCG compared to 69% and 43% for the “Tumor” group, respectively. There was no significant difference in alpha diversity ( p > 0.05). Beta diversity was significantly different ( p = 0.04). Veillonella and Bifidobacterium were more abundant in the “Tumor” group (> 2FC, p = 0.0002), while Escherichia - Shigella (> 2FC, p = 0.0002) and Helococcus (> 2FC, p = 0.0008) were more abundant in the “No Recurrent Tumor” group. Conclusion Bladder cancer patients with no recurrence and/or progression exhibited a different urinary microbiome profile compared to those with tumors.