Survival on the sweetest urinary protein A pilot study with uromodulin as a nutrient source for urogenital bacteria

Uromodulin (UMOD) is the most abundant glycoprotein in human urine, and its high-mannose content acts as a flushing ligand for uropathogenic Escherichia coli (UPEC). Nevertheless, many commensal bladder microbes, including Bifidobacterium longum, have the genetic capacity to digest N-glycans. Uromodulin could also serve as a nutrient reservoir for urinary bacteria capable of digesting N-glycans, as it has been demonstrated for other host glycoproteins and bacteria at other body sites. To test this hypothesis, we collected voided urogenital bacteria from male and female donors and assessed their survival aerobically on agar plates supplemented with 2% UMOD as the sole carbon source. After ten days, colonies were observed on UMOD-containing plates, picked and pooled, PCR-amplified, and then sequenced using universal 16S rRNA primers (27F and 1492R). Bioinformatics analysis showed that all identified species were previously observed in female and male urinary microbiome (urobiome) (e.g., Citrobacter koseri and Pseudomonas monteilii in female and male cases, respectively). Some of these bacteria are associated with the digestion of host glycans. This study is the first to demonstrate that urogenital bacteria from voided urine can aerobically utilize UMOD as a sole carbon source.