[Interactions between intestinal microbiota and Clostridioides difficile]

Interactions between intestinal microbiota and clostridioides difficile. Clostridioides difficile is a spore-forming anaerobic Gram-positive bacillus that is responsible for diarrhea and post-antibiotic colitis. Approximately 20,000 inpatients are infected by C. difficile in France per year. This bacterium is recognized as an emerging pathogen responsible for community-acquired diarrhea. Antibiotic therapy is the main risk factor for C. difficile infection (CDI) because it leads to intestinal dysbiosis and loss of "colonization resistance". C. difficile from endogenous or exogenous origin can then establish, multiply and produce its two toxins causing enterocyte lesions and a significant inflammatory reaction. The loss of colonization resistance has been associated with the loss of microbial diversity, particularly of some taxa that play a protective role. These variations of bacterial communities lead to changes in functions that can be explored by metabolomic or metagenomic approaches. Data from these experiments led to mechanistic assumptions about resistance or susceptibility to CDI. Microbiota studies have also pushed physicians to develop therapeutic approaches based on biotherapies. These therapies aim at repopulating the colon by a healthy microbiota either by fecal microbiota transplantation or by the administration of strains and cocktails of strains to restore the colonization resistance effect.