Can Gut Microbiota Analysis Reveal Clostridioides difficile Infection? Evidence from an Italian Cohort at Disease Onset

A diverse and well-functioning gut microbiota normally serves as a protective shield against the invasion of harmful bacteria or the proliferation of opportunistic pathogens. <i>Clostridioides difficile</i> infection (CDI) is predominantly associated with the overuse of antibiotics, resulting in a significant alteration in the gut's microbial balance. Unfortunately, the lack of global standardization does not allow for the identification of a set of biomarkers associated with the onset and progression of this disease. In this study, we examined the composition of the gut microbiota in patients at the time of the initial detection of CDI compared to a control group of CDI-negative individuals, with a focus on identifying potential CDI biomarkers for diagnosis. While no significant differences in the alpha and beta diversity between CDI-negative and CDI-positive individuals were found, we found that certain genera (such as <i>Clostridium</i> XIVa and <i>Clostridium</i> XVIII) showed different abundance patterns in the two groups, indicating potential differences in gut microbiota balance. In conclusion, am enrichment in <i>Clostridium</i> XI and a decrease in <i>Faecalibacterium</i> emerged in the CDI-positive patients and following antibiotic treatment, indicating that changes in the <i>Clostridium/Faecalibacterium</i> ratio may be a promising biomarker that warrants further investigation for CDI diagnosis.