Biliary Microbiota, Gallstone Disease and Infection with Opisthorchis felineus

Abstract

Background

There is increasing interest in the microbiome of the hepatobiliary system. This study investigated the influence of infection with the fish-borne liver fluke, Opisthorchis felineus on the biliary microbiome of residents of the Tomsk region of western Siberia.

Methodology/Principal Findings

Samples of bile were provided by 56 study participants, half of who were infected with O. felineus, and all of who were diagnosed with gallstone disease. The microbiota of the bile was investigated using high throughput, Illumina-based sequencing targeting the prokaryotic 16S rRNA gene. About 2,797, discrete phylotypes of prokaryotes were detected. At the level of phylum, bile from participants with opisthorchiasis showed greater numbers of Synergistetes, Spirochaetes, Planctomycetes, TM7 and Verrucomicrobia. Numbers of > 20 phylotypes differed in bile of the O. felineus-infected compared to non-infected participants, including presence of species of the genera Mycoplana, Cellulosimicrobium, Microlunatus and Phycicoccus, and the Archaeans genus, Halogeometricum, and increased numbers of Selenomonas, Bacteroides, Rothia, Leptotrichia, Lactobacillus, Treponema and Klebsiella.

Conclusions/Significance

Overall, infection with the liver fluke O. felineus modified the biliary microbiome, increasing abundance of bacterial and archaeal phylotypes.

Author Summary

The microbiota of the alimentary tract and other sites of the body influences human health. Contrary to popular belief, the bile within the liver is not sterile, and may host a microbiome consisting of diverse species of microbes. The spectrum of microbial species and their numbers within the biliary system may be influenced by disease including infection with pathogens such as parasitic worms and with gallstone disease, liver cancer and other ailments. Here we examined the microbes in the bile of patients from western Siberia, Russia who were concurrently infected with a food-borne parasitic worm, the liver fluke Opisthorchis felineus. Infection with this liver fluke is common in western Siberia, as a consequence of dietary preference for undercooked or smoked fresh-water fishes that often carry the larva of the liver fluke. Using high throughput sequencing targeting a conserved bacterial gene and statistical analyses, numerous bacterial species were identified in the bile of the patients. Infection with the liver fluke modified the biliary microbiome, resulting in abundant and diverse species of bacteria and Archaea.