Alterations of biliary and gut microbiota in relation to gallstone formation

Background: The gut and biliary microbiota are important components of the complex microecology system in the human body. However, it is often difficult to obtain bile in clinical practice to manage gallstone diseases, warranting further microbiota research to evaluate the relationship between biliary microbiota and gallstone formation. Aims: We aimed to characterize the diversity and alterations of biliary and gut microbiota in patients with gallstones and analyze their possible correlations to gallstone formation. Methods: We collected gallstones, bile, gallbladder mucosa, and feces from 21 patients with gallstone disease during operation and fecal samples from 20 healthy subjects without gallstones. We performed high-throughput sequencing of the V3-V4 regions of the 16S rRNA gene in the gallstone and control groups and analyzed the final optimization sequence. Results: We identified a total of 23,427 operational taxonomic units. Achromobacter (P = 0.010), Faecalibacterium (P = 0.042), and Lachnospira (P = 0.011) were significantly reduced, while Enterococcus (P = 0.001) was increased in the gallstone group. The diversity and composition between the biliary and gut microbiota in gallstone patients had statistical differences. The diversity of gut microbiota was significantly higher than that of biliary microbiota (P < 0.05). In addition, linear discriminant analysis (LDA) >4 indicated that the characteristic flora was specific to five samples. Prevotella and Proteobacteria had LDA values >4 in the feces and both bile and gallbladder mucosa, respectively, of patients with gallstones. Conclusion: The biliary and gut microbiota of patients with gallstones displayed bacterial heterogeneity. Prevotella and Proteobacteria may serve as biomarkers for dysbacteriosis in patients with gallstones, suggesting that alterations of biliary and gut microbiota are involved in the formation of gallstones. This study highlights the potential application of fecal microbiota transplantation technology in the treatment of gallstone diseases. Relevance for Patients: Microecology of the digestive tract is closely related to the formation of gallstones, providing new ideas for the prevention and treatment of patients with gallstones.