Altered blood microbiome in patients with HCV-related decompensated cirrhosis.
Background: Bacterial translocation is essential in transitioning from compensated to decompensated cirrhosis. In this context, the presence in the blood of certain bacteria or the finding of specific microbiome patterns, could constitute an innovative approach for a better understanding of the pathogenesis of advanced hepatitis C virus (HCV)-related cirrhosis. We aimed to study differences in the blood microbiome of HCV-infected patients with and without hepatic decompensation.?   Methods: We conducted a cross-sectional study in patients with advanced HCV-related cirrhosis with or without human immunodeficiency virus (HIV) infection (n=88). MiSeq Illumina technology for bacterial 16S rRNA sequencing was used. Non-targeted metabolomics was performed by GC-MS and LC-MS ESI+ and ESI-.?   Results: Patients with decompensated cirrhosis had lower levels of richness [Chao1 (adjusted arithmetic mean ratio (aAMR)=0.85, p=0.021)], and alpha diversity [Shannon (aAMR=0.80, p=0.005) and Simpson indexes (aAMR=0.83, p=0.006)] at phylum level, than patients without decompensation. Likewise, we observed significant differences in beta diversity between groups at phylum, class and order levels, being lower in decompensated cirrhotic patients. Higher relative abundance of Proteobacteria (Fold Change (FC)=1.54, p=0.012), Alphaproteobacteria (FC=1.57, p=0.016) and Sphingomonadales (FC=1.61, p=0.050) were significantly associated with hepatic decompensation. The phylum Proteobacteria was positively correlated with ethanolamine and oleic acid (p=0.005 and p=0.004, respectively) and negatively with p-cresol (p=0.006). In addition, the order Sphingomonadales was also negatively correlated with p-cresol (p=0.001)?   Conclusions: Blood microbial diversity was significantly decreased in patients with decompensated cirrhosis, who presented an enrichment of Proteobacteria, Alphaproteobacteria, and Sphingomonadales, compared to patients with compensated cirrhosis.?