Fecal microbiota transplantation (FMT) achieves the purpose of treating intestinal and extra-intestinal diseases by transplanting the functional microbes in the feces of healthy people into the patient's intestine through the upper or lower alimentary tract routes to rebuild the patient's intestinal microbiota. Recently, FMT has been widely used in the treatment of various gastrointestinal diseases, including but not limit in CDI. In this study, we focused on the demonstration of FMT action mechanism in CDI treatment.

Inclusion Criteria:

1. aged over 18 years old;
2. positive stool test for Clostridium difficile 16S rDNA and/or glutamate dehydrogenase;
3. can tolerate nasojejunal tube and complete full course of FMT treatment;
4. the clinical data are relatively complete and there is follow-up available for evaluation

Exclusion Criteria:

1. accompanied by chronic wasting diseases such as malignant tumor and hyperthyroidism;
2. associated with gastrointestinal organic diseases such as short bowel syndrome, intestinal fistula, and inflammatory bowel disease; c) severe destruction of the intestinal mucosa, severe immunosuppression, combined with severe systemic infection; d) Intervention with antibiotics during treatment