Reuterin disrupts metabolism and pathogenicity through reactive oxygen species generation.

Antibiotic resistance is one of the world's greatest public health challenges and adjunct probiotic therapies are strategies that could lessen this burden. infection (CDI) is a prime example where adjunct probiotic therapies could decrease disease incidence through prevention. Human-derived is a probiotic that produces the antimicrobial compound reuterin known to prevent colonization of antibiotic-treated fecal microbial communities. However, the mechanism of inhibition is unclear. We show that reuterin inhibits outgrowth from spores and vegetative cell growth, however, no effect on germination or sporulation was observed. Consistent with published studies, we found that exposure to reuterin stimulated reactive oxygen species (ROS) in , resulting in a concentration-dependent reduction in cell viability that was rescued by the antioxidant glutathione. Sublethal concentrations of reuterin enhanced the susceptibility of vegetative to vancomycin and metronidazole treatment and reduced toxin synthesis by . We also demonstrate that reuterin is protective against toxin-mediated cellular damage in the human intestinal enteroid model. Overall, our results indicate that ROS are essential mediators of reuterin activity and show that reuterin production by is compatible as a therapeutic in a clinically relevant model.