The Urinary Tract Microbiome in Older Women Exhibits Host Genetic and Environmental Influences.

The urinary microbiome is a relatively unexplored niche that varies with gender. Urinary microbes, especially in aging populations, are associated with morbidity. We present a large-scale study exploring factors defining urinary microbiome composition in community-dwelling older adult women without clinically active infection. Using 1,600 twins, we estimate the contribution of genetic and environmental factors to microbiome variation. The urinary microbiome is distinct from nearby sites and unrelated to stool microbiome with more Actinobacteria, Fusobacteria and Proteobacteria, but fewer Bacteroidetes, Firmicutes and Verrumicrobia. A quarter of variants had heritability estimates greater than 10% with most heritable microbes having potential clinical relevance, including Escherichia-Shigella linked to urinary tract infections. Age, menopausal status, prior UTI, and host genetics were top factors defining the urobiome with increased microbial diversity tending to associate with older age. These findings highlight the distinct composition of the urinary microbiome and significant contributions of host genetics.