The Impact of Gender on Urine Microbial Communities and Urine Metabolites: A Comprehensive Analysis Using High-Throughput 16S rRNA Sequencing and Metabolomics

Background: Recent scientific investigations have significantly advanced our understanding of the urinary microbiome, revealing that the urinary tract harbors complex microbial ecosystems that play crucial roles in physiological homeostasis and various aspects of overall health. These microbial communities show notable variations influenced by individual health conditions and biological sex. However, comparative analyses of urinary microbiota composition between adult males and females remain relatively scarce. Moreover, the biological mechanisms through which sex differences influence these microbial populations have not been fully clarified. To address these knowledge gaps, the present study conducted a comprehensive examination of microbial diversity patterns and associated metabolomic profiles in urine samples collected from healthy adult male and female participants. This was achieved by employing cutting-edge high-throughput 16S rRNA gene sequencing techniques, along with advanced metabolomic approaches, to elucidate potential sex-specific mechanisms. Results: The research findings demonstrated significant sex-based differences in urinary microbiome characteristics. Female participants exhibited substantially reduced microbial diversity compared to males, as evidenced by significantly lower Shannon diversity indices (4.15 versus 5.96, p=0.0006). Taxonomic profiling revealed distinct microbial community structures between sexes, with female urine samples predominantly colonized by Gardnerella and Prevotella genera, while male samples showed characteristic enrichment of Ralstonia, Elizabethkingia, Dubosiella, and Proteus genus. Functional annotation of microbial communities uncovered important physiological differences. Female-associated microbiota contained significantly higher proportions of anaerobic and Gram-positive bacterial genera (p<0.05), but notably fewer stress-tolerant bacteria, potentially pathogenic organisms, facultative anaerobes, aerobic microorganisms, and Gram-negative bacteria (p<0.05). Furthermore, metabolomic analyses identified 190 differentially abundant metabolites between sexes, including 19 metabolites significantly elevated in females and 171 metabolites preferentially accumulated in males, with particularly prominent differences observed in amino acid and lipid metabolic pathways. Network correlation analyses revealed striking inverse relationships between female-dominant bacterial taxa and the top 20 most abundant metabolites (R < -0.8, p < 0.05), whereas male-associated bacteria demonstrated strong positive correlations with these metabolites (R > 0.8, p < 0.05). Conclusions: These comprehensive findings offer valuable foundational data on gender-specific normal urinary microbiota. Furthermore, the study underscores the potential clinical utility of implementing routine screening protocols targeting both urinary microbiome composition and metabolic signatures. This approach can enhance precision in personalized medicine considering gender differences for various urological conditions and improve urinary health outcomes.