Intestinal microbiota in patients with chronic hepatitis C with and without cirrhosis compared with healthy controls

Background & Aims The importance of the intestinal microbiota for the onset and clinical course of many diseases, including liver diseases like non‐alcoholic steatohepatitis and cirrhosis, is increasingly recognized. However, the role of intestinal microbiota in chronic hepatitis C virus ( HCV ) infection remains unclear. Methods In a cross‐sectional approach, the intestinal microbiota of 95 patients chronically infected with HCV (n=57 without cirrhosis [ NO ‐ CIR ]; n=38 with cirrhosis [ CIR ]) and 50 healthy controls ( HC ) without documented liver diseases was analysed. Results Alpha diversity, measured by number of phylotypes (S) and Shannon diversity index (H′), decreased significantly from HC to NO ‐ CIR to CIR . S and H′ correlated negatively with liver elastography. Analysis of similarities revealed highly statistically significant differences in the microbial communities between HC , NO ‐ CIR and CIR ( R =.090; P <1.0×10 −6 ). Stratifying for HCV genotypes even increased the differences. In addition, we observed distinct patterns in the relative abundance of genera being either positive or negative correlated with diseases status. Conclusions This study shows that not only the stage of liver disease but also HCV infection is associated with a reduced alpha diversity and different microbial community patterns. These differences might be caused by direct interactions between HCV and the microbiota or indirect interactions facilitated by the immune system.