The bacteria of the intestinal microbiota are known for their numerous physiological roles: digestion of food, regulation of the immune system, communication with the brain, neural development, among other functions. The composition of microbiota is specific to each individual. Some bacterial strains are beneficial to the host and are called commensal bacteria. These bacteria have established a symbiotic relationship with the human organism to ensure their survival, in exchange for the assurance of the physiological roles previously mentioned. A change in the composition of the intestinal microbiota, the loss of certain important strains in favor of pathogenic strains, can lead to diseases. This deleterious modification is called dysbiosis. It can occur due to genetic or environmental factors, lifestyle, diet, or even medication. More specifically, the prolonged administration of antibiotics is often associated with dysbiosis. Several pathologies have been associated with this condition: Clostridioides difficile infection (CDI), inflammatory bowel disease, autism spectrum syndrome, obesity, among others. This thesis project focuses on CDI and more specifically on the bacteria of the gut microbiota.