Biliary microbiota and bile acids composition in cholelithiasis

Background A functional interplay between BAs and microbial composition in gut is a well-documented phenomenon. In bile this phenomenon is far less studied and with this report we describe the interactions between the BAs and microbiota in this complex biological matrix.

Methodology Thirty-seven gallstone disease patients of which twenty-one with Opisthorchis felineus infection were enrolled in the study. The bile samples were obtained during laparoscopic cholecystectomy for gallstone disease operative treatment. Common bile acids composition were measured by LC-MS/MS using a column in reverse phase. For all patients gallbladder microbiota was previously analyzed with 16S rRNA gene sequencing on Illumina MiSeq platform. The associations between bile acids composition and microbiota were analysed.

Principal findings Bile acids signature and O. felineus infection status exerts influence on beta-diversity of bile microbial community. Direct correlations were found between taurocholic acid, taurochenodeoxycholic acid concentrations and alpha-diversity of bile microbiota. Taurocholic acid and taurochenodeoxycholic acid both shows positive associations with the presence of Chitinophagaceae family, Microbacterium and Lutibacterium genera and Prevotella intermedia. Also direct associations were identified for taurocholic acid concentration and the presence of Actinomycetales and Bacteroidales orders, Lautropia genus, Jeotgalicoccus psychrophilus and Haemophilus parainfluenzae as well as for taurochenodeoxycholic acid and Acetobacteraceae family and Sphingomonas genus. There were no differences in bile acids concentrations between O. felineus infected and non-infected patients.

Conclusions/Significance Associations between diversity, taxonomic profile of bile microbiota and bile acids levels were evidenced in patients with cholelithiasis. Increase of taurochenodeoxycholic acid and taurocholic acid concentration correlates with bile microbiota alpha-diversity and appearance of opportunistic pathogens. Alteration of bile acids signature could cause shifts in bile microbial community structure.