Next-Generation Probiotics Targeting Clostridium difficile through Precursor- Directed Antimicrobial Biosynthesis

Authors

Jennifer K. Spinler, Texas Children’s HospitalFollow
Jennifer Auchtung, Baylor College of MedicineFollow
Aaron Brown, Baylor College of Medicine
Prapaporn Boonma, Baylor College of Medicine
Numan Oezguen, Baylor College of Medicine
Cana L. Ross, Baylor College of Medicine
Ruth Ann Luna, Baylor College of Medicine
Jessica Runge, Baylor College of Medicine
James Versalovic, Baylor College of Medicine
Alex Peniche, University of Texas Medical Branch
Sara M. Dann, University of Texas Medical Branch
Robert A. Britton, Baylor College of Medicine
Anthony Haag, Baylor College of Medicine
Tor C. Savidge, Baylor College of Medicine

ORCID IDs

0000-0002-7830-7665

Document Type

Article

Date of this Version

2017

Citation

Infect Immun 85:e00303-17.

Comments

© 2017 American Society for Microbiology.

https://doi.org/10.1128/IAI.00303-17

Abstract

Integration of antibiotic and probiotic therapy has the potential to lessen the public health burden of antimicrobial-associated diseases. Clostridium difficile infection (CDI) represents an important example where the rational design of next-generation probiotics is being actively pursued to prevent disease recurrence. Because intrinsic resistance to clinically relevant antibiotics used to treat CDI (vancomycin, metronidazole, and fidaxomicin) is a desired trait in such probiotic species, we screened several bacteria and identified Lactobacillus reuteri to be a promising candidate for adjunct therapy. Human-derived L. reuteri bacteria convert glycerol to the broad-spectrum antimicrobial compound reuterin. When supplemented with glycerol, strains carrying the pocR gene locus were potent reuterin producers, with L. reuteri 17938 inhibiting C. difficile growth at a level on par with the level of growth inhibition by vancomycin. Targeted pocR mutations and complementation studies identified reuterin to be the precursor-induced antimicrobial agent. Pathophysiological relevance was demonstrated when the codelivery of L. reuteri with glycerol was effective against C. difficile colonization in complex human fecal microbial communities, whereas treatment with either glycerol or L. reuteri alone was ineffective. A global unbiased microbiome and metabolomics analysis independently confirmed that glycerol precursor delivery with L. reuteri elicited changes in the composition and function of the human microbial community that preferentially targets C. difficile outgrowth and toxicity, a finding consistent with glycerol fermentation and reuterin production. Antimicrobial resistance has thus been successfully exploited in the natural design of human microbiome evasion of C. difficile, and this method may provide a prototypic precursor-directed probiotic approach. Antibiotic resistance and substrate bioavailability may therefore represent critical new determinants of probiotic efficacy in clinical trials.