Bile microbiota: new insights into biliary complications in liver transplant recipients

Abstract

Background: Biliary complications represent a major problem associated with liver transplantation. This report represents the first study to use high-throughput 16S ribosomal RNA (rRNA) gene sequencing to assess bile microbiota within bile samples of liver transplant recipients with biliary complications. Our goal in this report was to identify the species and abundance of microbes and examine the potential for microbial involvement of bile in liver transplantation patients with biliary complications.Methods: Liver transplant recipients treated at our center over the period from September 2015 to June 2017 were enrolled in the study. Patients satisfying the inclusion criteria were divided into two groups, control (N=13) and symptom (N=10). Sequencing of 16s rDNA was then performed on bile samples from both groups. Results:The main bacterial phyla of bile samples in the symptom group included Proteobacteria (55.19%), Firmicutes (32.36%), Actinobacteria (10.24%) and Bacteroidetes (1.23%) and the main bacterial genera were Pseudomonas (23.31%), Klebsiella (18.42%), Lactococcus (9.61%), Rhodococcus (9.59%) and Rhizobium (5.08%).Proteobacteria and Staphylococcus were enriched in the symptom group (P<0.05), whereas Firmicutes (P<0.05) and Enterococcus (P<0.01) were enriched in the control group. Pathways involved as determined with use of the Kyoto Encyclopedia of Genes and Genomes (KEGG), revealed that metabolism pathways of glyoxylate and dicarboxylate, porphyrin and chlorophyll, arginine and proline, glycine, serine and threonine, as well as the bacterial secretion system were all enriched in bile samples from the symptom group (P<0.05).Conclusions: Clear differences exist in microbial species distribution in bile samples from the symptom versus control group. The species and pathways enriched in bile samples within the symptom group may be involved in the pathogenesis of biliary complication after liver transplantation.

Biliary Diseases from the Microbiome Perspective: How Microorganisms Could Change the Approach to Benign and Malignant Diseases

“…Later, the composition of the bile microbiome by was confirmed culture-based techniques by a smaller prospective study [144]. Only in the studies by Liu et al [145,146] was the bile microbiota assessed by 16S-rRNA gene sequencing. The authors found that the most common genera were Enterococcus, Rhizobium, Nevskia, Lactococcus, Bacillus, Clostridium sensu strictu, Stenotrophomonas, Pseudomonas, Streptococcus, and Aeromona.…”

An Italian survey on the use of T-tube in liver transplantation: old habits die hard!

“…Bile acids regulate the gut microbiome structure by controlling gut bacteria composition and overgrowth by a selective antimicrobial effect, and protecting the epithelial barrier via farnesoid X receptor signaling [ 23 ]. Therefore, bile diversion through a T-tube in the early post-transplant period may result in gut microbiota changes, which have recently been shown to be associated with potential long-term inflammatory, metabolic and immune effects [ 24 ]. Moreover, hepatic bile acids have recently been identified as important mediators of early liver regeneration [ 7 , 25 ].…”

Analysis of the relationship between bile duct and duodenal microbiota reveals that potential dysbacteriosis is the main cause of primary common bile duct stones

“…At the genus level, the most dominant genus was Pseudomonas of the phylum Proteobacteria , followed by Escherichia-Shigella . Although they are classic contaminants [ 32 ], this does not invalidate the results as it has been shown that they are common in the small intestine and bile [ 33 , 34 ]. This is different from previous research results, Ye et al found three Enterobacteriaceae genera ( Escherichia , Klebsiella , and an unclassified genus) and Pyramidobacter were abundant in bile of six gallstone patients, while Li et al found Acinetobacter and Prevotella were dominant genera in the duodenum of nine healthy volunteers [ 7 , 35 ].…”