The Relationship between Urinary Stones and Gut Microbiomeby 16S Sequencing.

objectiveTo understand the relationship between urinary stones and the gut microbiome and to screen for microbial species that may be involved in stone formation.

methodsStool samples were collected from patients with urolithiasis and healthy patients between March and December 2017. The samples were analyzed by 16S sequencing to determine differences in the microbiome profiles between the two groups. The mouse model was established and was divided into two groups. Fecal samples were collected from the mice before gavage and three weeks postgavage for microbiome analysis. The microbial population of each group was analyzed to screen for microbial species that may affect the formation of urinary stones. Differences in the number of crystals in the renal tubules of the mice were examined by necropsy.

resultsThe microbial composition was different between urolithiasis patients and healthy controls. The urolithiasis patients had significantly reduced microbial abundance; however, increased proportions of Bacteroidetes and Actinobacteria were detected compared to healthy controls. Furthermore, the abundance of Alistipesindistinctus and Odoribactersplanchnicus was significantly increased in the urolithiasis patients compared to the healthy controls. In addition, the incidence of urolithiasis was much higher in the experimental mouse group (stone solution + urolithiasis patient stool) than in the control mouse group. However, the microbial abundance before gavage was not significantly different from that seen three weeks postgavage.

conclusionTheurolithiasis patients in this study had a different gut microbiome when compared with that of healthy individuals. The altered microbiome increased the rate of crystal formation in renal tubules and accelerated urinary stone formation in the mouse model of urolithiasis.