Clostridioides difficile (C. difficile) colitis is a common hospital-acquired disease, which increases hospitalization length and the mortality rate. Moreover, refractory or recurrent C. difficile colitis is an emerging disease. The tapering course of oral vancomycin or oral fidaxomicin is current standard treatment for refractory or recurrent C. difficile colitis. Fecal microbiota transplantation (FMT) is an alternative one. However, the tapering course of oral vancomycin needs a 6- to 12-week duration, fidaxomicin is expensive, and FMT is not available in every hospital; therefore, it is needed to develop a new treatment. Evidence has shown that the disturbance with reduced diversity of intestinal microbiota may lead to refractory C. difficile colitis. Besides fecal microbiota transplantation, probiotics administration can also correct the disturbed intestinal microbiota. However, inconsistent efficacy of probiotic administration was reported, which may be attributed to the interference by the gastric acid. Precise delivery of probiotics into the colon by colonoscopy can avoid the destruction by gastric acid, with which a better treatment efficacy is expected. The best regimen for C. difficile colitis should be the one which succeeds on the first attempt. Therefore, this study is aimed toward validating the efficacy and safety of the colonoscopic probiotics-spray.

Patients diagnosed with C. colitis will be enrolled. All patients will accept the standard treatment of oral vancomycin for 14 days. As an adjuvant probiotic administration at the same time, enrolled patients will be randomly assigned to the probiotics-spray (PS) group and the probiotics-oral (PO) group, respectively. The patients in the PS group will receive colonoscopic spray of probiotics once, while the patients in the PO group will receive the same dosage of oral probiotics divided into 5 days. This study will compare the difference in fecal microbiota changes between the colonoscopic probiotics-spray group and the probiotics-oral group. Moreover, this study will evaluate the efficacy and safety between the colonoscopic probiotics-spray and probiotics-oral in patients with C. difficile colitis.

Refractory or recurrent C. difficile colitis is an emerging disease. The tapering course of oral vancomycin or oral fidaxomicin is current standard treatment for refractory or recurrent C. difficile colitis.FMT is an alternative treatment. Nevertheless, the tapering course of oral vancomycin needs a 6- to 12-week duration, fidaxomicin is expensive, and FMT is not available in many hospitals. Therefore, we need a method which is effective for patients and available for clinicians.

The disturbance with reduced diversity of intestinal microbiota may lead to refractory or recurrent C. difficile colitis. Moreover, the probiotics administration can correct the disturbed intestinal microbiota. However, inconsistent efficacy of probiotic administration was reported, which may be attributed to the interference by the gastric acid. There is no exact estimation for the amounts of probiotics in the colon after oral administration. Moreover, there is no study which is conducted to compare the efficiency of probiotics between direct spray via colonoscopy and oral administration. It will be novel to study such issue. If the amounts of probiotics which is delivered directly via colonoscopy and the clinical efficacy are similar to those by FMT, colonoscopic probiotics-spray will replace FMT in clinical practice.

FMT can correct the disturbed intestinal microbiota. The estimated bacteria of human wet stool are 1011 per gram. The amount of stool for FMT is ~30 to 100 grams; thus, ~1012 to 1013 bacteria will be transplanted in an FMT procedure. In this project, we will transplant ~2x1011 probiotics into the colon by the colonoscopic spray. Therefore, we believe that colonoscopic spray of probiotics will have similar amounts of bacteria transplanted with FMT but be more efficient than oral probiotics administration.

Probiotics use may have adverse events. There are few studies and case reports which recorded that the administered probiotic was isolated from sterile sites, such as bacteremia. Thus, the safety issue of this study will focus on the adverse events, bacteremia and sepsis.

It will be novel to conduct the study to compare the efficacy and safety of probiotics which are delivered directly via colonoscopy and oral administration. If it works, colonoscopic probiotics spray will replace FMT in clinical practice.

Inclusion Criteria:

• patients aged ≥ 20 years who are diagnosed with C. difficile colitis

Exclusion Criteria:

• patients are diagnosed with colitis because of other etiologies, such as intestinal Behçet's disease, amoeba or parasitic colitis, Salmonella colitis, lymphoma, E. coli colitis, cytomegalovirus colitis, ischemic colitis, sigmoid-colon cancer, inflammatory bowel diseases (ulcerative colitis or Crohn's disease), solitary rectal ulcer syndrome, radiation colitis
• patients who have contraindications for colonoscopy, including declining or refusal to cooperate
• unstable vital signs
• a diagnosis or highly suspicion of colon rupture
• a high-risk situation for colon perforation such as acute diverticulitis
• toxic megacolon, etc.
• acute myocardial infarct

IPD sharing after the study completed and the paper published