Metagenetic approach to explore the gut microbiota and their secreted extracellular vesicles in diarrheic and healthy patients.

The release of membrane-bound vesicles is a conserved cellular process. Gram-positive and Gram-negative secrete nanometer-scale extracellular membrane vesicles (EMV) with important biological functions, including immune-response regulation, long distance transport of virulence factors, lateral transfer of antibiotic resistance genes, or RNA transfer agents, among others. For Clostridium difficile (C. difficile), these vesicles have been associated with the infection (CDI), since they can induce the expression of pro-inflammatory genes and epithelial cells cytotoxicity.The aim of this study was to evaluate the microbial diversity of feces and secreted EMV in healthy patients, diarrheic patients and patients with CDI. The link between microbiota composition and their derived EMV could reveal newt insights into the microbial activities in the host. Furthermore, the identification of these changes opens up new possibilities of disease diagnostic and assessment.
EMV were enriched in the 3 groups of patients, but their composition differed significantly between them. Regarding global differences between feces and EMV, Lachnoclostridium and Streptococcus were more abundant in feces, but their vesicles production was limited and dominated by Faecalibacterium. At genus level, proportions of Clostridioides, Staphylococcus and Enterococcus were significantly higher in vesicles from CDI patients than in the other groups. These findings suggest that the increased production of EMV by these taxa could be associated with the dysbiosis establishment, and therefore with the development of the infectious disease. More extensive research to investigate the specific role of the identified EMV in the CDI is now warranted.