“…Intestinal Clostridiaceae are subdivided into 19 clusters with 120 species, and their growth is suppressed by other anaerobes in a healthy gut [ 73 ]. When alterations of the microbiota and the intestinal microenvironment occur, for example, following treatments with antibiotics, proton pump inhibitors, and chemotherapy or when there are associated comorbidities (inflammatory bowel disease, diabetes mellitus, cancer, and pancreatitis) or recent hospitalizations, this creates the premises for C. difficile expansion and subsequent infection [ 74 , 75 ]. Therefore, it was shown that for the elderly, where the infection with C. difficile is nonresponsive to treatment with metronidazole or vancomycin and is lethal in 15% of cases, the most beneficial intervention is the correction of the microbiota through fecal transplantation [ 76 ].…”