Inhibiting Growth of Clostridioides difficile by Restoring Valerate, Produced by the Intestinal Microbiota

Gastroenterology. 2018 Nov;155(5):1495-1507.e15. doi: 10.1053/j.gastro.2018.07.014. Epub 2018 Jul 17.


Background & aims: Fecal microbiota transplantation (FMT) is effective for treating recurrent Clostridioides difficile infection (CDI), but there are concerns about its long-term safety. Understanding the mechanisms of the effects of FMT could help us design safer, targeted therapies. We aimed to identify microbial metabolites that are important for C difficile growth.

Methods: We used a CDI chemostat model as a tool to study the effects of FMT in vitro. The following analyses were performed: C difficile plate counts, 16S rRNA gene sequencing, proton nuclear magnetic resonance spectroscopy, and ultra-performance liquid chromatography and mass spectrometry bile acid profiling. FMT mixtures were prepared using fresh fecal samples provided by donors enrolled in an FMT program in the United Kingdom. Results from chemostat experiments were validated using human stool samples, C difficile batch cultures, and C57BL/6 mice with CDI. Human stool samples were collected from 16 patients with recurrent CDI and healthy donors (n = 5) participating in an FMT trial in Canada.

Results: In the CDI chemostat model, clindamycin decreased valerate and deoxycholic acid concentrations and increased C difficile total viable counts and valerate precursors, taurocholic acid, and succinate concentrations. After we stopped adding clindamycin, levels of bile acids and succinate recovered, whereas levels of valerate and valerate precursors did not. In the CDI chemostat model, FMT increased valerate concentrations and decreased C difficile total viable counts (94% decrease), spore counts (86% decrease), and valerate precursor concentrations; concentrations of bile acids were unchanged. In stool samples from patients with CDI, valerate was depleted before FMT but restored after FMT. Clostridioides difficile batch cultures confirmed that valerate decreased vegetative growth, and that taurocholic acid was required for germination but had no effect on vegetative growth. Clostridioides difficile total viable counts were decreased by 95% in mice with CDI given glycerol trivalerate compared with phosphate buffered saline.

Conclusions: We identified valerate as a metabolite that is depleted with clindamycin and only recovered with FMT. Valerate is a target for a rationally designed recurrent CDI therapy.

Keywords: Bacteria; Gut Microbiome; Pathogen; Stool Transplant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bile Acids and Salts / analysis
  • Chromatography, High Pressure Liquid
  • Clindamycin / pharmacology
  • Clostridioides difficile / drug effects*
  • Clostridioides difficile / growth & development
  • Clostridium Infections / therapy*
  • Feces / chemistry
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Gastrointestinal Microbiome*
  • Magnetic Resonance Spectroscopy
  • Mice, Inbred C57BL
  • Spores, Bacterial
  • Triglycerides / therapeutic use
  • Valerates / metabolism
  • Valerates / pharmacology*


  • Bile Acids and Salts
  • Triglycerides
  • Valerates
  • Clindamycin
  • glycerol trivalerate