This study will test the safety and effectiveness of fecal microbiota transplantation (FMT) plus partial enteral nutrition (PEN) in refractory pediatric Crohn's disease (CD) who have failed conventional treatment

Recent studies have suggested that gut imbalance and deregulation of immunological responses plays a pivotal role in the disease development of Crohn's disease (CD), and that FMT could be a useful treatment. Our study is aims to repeated and multiple FMTs plus PEN in the treatment of refractory pediatric CD. In the induction stage of CD, standard therapy remained unchanged, FMT and PEN were added, and FMT was given 1-2 courses, 3-6 times per course. In the maintaining stage, FMT was performed every 3 months, with the same 3-6 times of FMT treatment for each course, and the withdrawal of conventional drug therapy was gradually reduced. Refractory CD was defined as refractory to standard therapy (e.g., steroids, immunomodulators, cyclosporine, tacrolimus, or anti-TNF agents).

Inclusion Criteria:

Aged 2-16 years and without genetic diseases; All refractory pediatric with mild-to-moderate CD; Mild-to-moderate CD, defined by the pediatric Crohn's disease activity index (PCDAI) >10 and ≤40 and Simple Endoscopic Score for CD (SES-CD) > 3 were enrolled in the study; refractory CD, defined by children who failed conventional treatment (hormone, immunosuppressant, biologics)

Exclusion Criteria Children who were treated by PEN (80%) less than 8 weeks; follow up less than 3 months; known contraindication to all FMT infusion method such as nasoduodenal tube insertion, oesophago-gastro-duodenoscopy (OGD), enteroscopy, colonoscopy, enema and Fecal capsule; unwilling to give informed consent/assent