Dysbiosis of the Human Urinary Microbiome and its Association to Diseases Affecting the Urinary System

The human urinary microbiome, also termed urobiome, has been overlooked due to the clinical dogma of sterile urine, as reported by routine culture. However, evolving sensitive tools such as expanded quantitative urine culture, 16S ribosomal RNA gene sequencing, and next-generation sequencing have discovered a vast number of microorganisms present in urine, even in healthy individuals. Microbiome dysbiosis and its links to disease is a heavily explored area in several microbial niches. Presently, urobiome dysbiosis and its correlation to urinary system-related diseases is at its infancy but rapidly emerging, as it provides potential therapeutic insights. This review outlines the changes in the human urinary microbiome concerning globally prevalent diseases affecting kidney function, such as chronic kidney disease (CKD), diabetes mellitus (DM), hypertension (HT), and urinary tract infection (UTI). Alterations to urine microbial diversity, including differences in the abundance and species richness of particular microbial genera, notably Lactobacillus, Prevotella, Streptococcus, Staphylococcus, Klebsiella, Enterococcus, between diseased and healthy samples are discussed utilising studies to date. Subsequent research needs to move beyond correlation to understand the roles of the urinary microbiota in diseases, thereby clarifying whether urinary dysbiosis has causal contributions that may provide important insight for diagnostics, pathophysiology, and therapy in renal pathologies.