Clostridioides Difficile Colonization Is Not Mediated by Bile Salts and Utilizes Stickland Fermentation of Proline in an in Vitro Model

Authors

Xiaoyun Huang
April E Johnson
Joshua N Brehm
Thi Van Thanh Do
Thomas A Auchtung
Hugh C McCullough
Armando I Lerma
Sigmund J Haidacher
Kathleen M Hoch
Thomas D Horvath
Joseph A Sorg
Anthony M Haag
Jennifer M Auchtung

Language

English

Publication Date

2-25-2025

Journal

mSphere

DOI

10.1128/msphere.01049-24

PMID

39817755

PMCID

PMC11852769

PubMedCentral® Posted Date

1-16-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Treatment with antibiotics is a major risk factor for Clostridioides difficile infection, likely due to depletion of the gastrointestinal microbiota. Two microbiota-mediated mechanisms thought to limit C. difficile colonization include the conversion of conjugated primary bile salts into secondary bile salts toxic to C. difficile growth and competition between the microbiota and C. difficile for limiting nutrients. Using a continuous flow model that simulates the nutrient conditions of the distal colon, we investigated how treatment with 6 clinically used antibiotics influenced susceptibility to C. difficile infection in 12 different microbial communities cultivated from healthy individuals. Antibiotic treatment reduced microbial richness; disruption varied by antibiotic class and microbiota composition, but did not correlate with C. difficile susceptibility. Antibiotic treatment also disrupted microbial bile salt metabolism, increasing levels of the primary bile salt, cholate. However, changes in bile salt did not correlate with increased C. difficile susceptibility. Furthermore, bile salts were not required to inhibit C. difficile colonization. We tested whether amino acid fermentation contributed to the persistence of C. difficile in antibiotic-treated communities. C. difficile mutants unable to use proline as an electron acceptor in Stickland fermentation due to disruption of proline reductase (prdB−) had significantly lower levels of colonization than wild-type strains in four of six antibiotic-treated communities tested. The inability to ferment glycine or leucine as electron acceptors, however, was not sufficient to limit colonization in any communities. The data provide further support for the importance of bile salt-independent mechanisms in regulating the colonization of C. difficile.

Keywords

Bile Acids and Salts, Clostridioides difficile, Proline, Fermentation, Anti-Bacterial Agents, Humans, Gastrointestinal Microbiome, Clostridium Infections, Stickland fermentation, antibiotic disruption, bile metabolism, microbiota

Published Open-Access

yes

Recommended Citation

Huang, Xiaoyun; Johnson, April E; Brehm, Joshua N; et al., "Clostridioides Difficile Colonization Is Not Mediated by Bile Salts and Utilizes Stickland Fermentation of Proline in an in Vitro Model" (2025). Faculty and Staff Publications. 5655.
https://digitalcommons.library.tmc.edu/baylor_docs/5655