Effect of Clostridioides difficile infection on the structure and functions of the human gut microbiota

Clostridioides difficile is a spore forming pathobiont that colonizes the human intestine. Germination and toxins production, most commonly occurring after use of antibiotic medications, lead to diarrhea, pseudomembranous colitis and toxic megacolon, with an imbalance of the gut microbiota taxonomic structure. No studies have yet described the functional and the taxonomic variations occurring in the gut microbiota in the context of C. difficile disease. Our aim was to profile the intestinal metaproteome functional features specifically associated to C. difficile colonization and toxigenic activity. No differences were observed between the three sample groups regard to richness and beta diversity. Our data highlight the impact of C. difficile presence on both the taxonomic and functional features of the gut microbiota: the genus Anaerostipes was significantly higher in the microbiota of positive patients (compared to N), whereas that of Ruminococcus peptides was significantly higher in the microbiota of N patients. Moving to functional results, total abundance of peptides associated with histidine metabolism were found significantly higher in the microbiota of patients belonging to the Tp group when compared to those from the N and Tg group, respectively. Same results were obtained for functions related to Glucuronate pathway and Ascorbate biosynthesis pathways.