Shotgun metagenomics reveals significant gut microbiome features in different grades of acute pancreatitis

Acute pancreatitis (AP) has a broad spectrum of severity and is associated with considerable morbidity and mortality. Dysbiosis of gut microbiota may be associated with AP severity. We aimed to evaluate the composition and functional effects of gut microbiota in different grades of AP severity. We carried out shotgun metagenomic sequencing on rectal swab samples from three patients with mild acute pancreatitis (MAP), three with moderately severe acute pancreatitis (MSAP), three with severe acute pancreatitis (SAP) and three normal control persons (NOR). Differences analysis in gut microbiota composition and functional enrichment was performed. Gut microbiota in AP patients was characterized by decreased species richness. The most representative gut microbiota in mild acute pancreatitis (MAP), moderately severe acute pancreatitis (MSAP), and severe acute pancreatitis (SAP) was Streptococcus, Escherichia-coli, and Enterococcus, respectively. Each of the three AP-associated genera could differentiate AP from healthy control population. Representative pathways associated with the glutathione metabolism, lipopolysaccharide biosynthesis, and amino acid metabolism (valine, leucine and isoleucine degradation) were enriched in MAP, MSAP, and SAP, respectively. The study shows a potential association of gut microbiome composition and function to the progression of AP severity.