Combination of mitomycin C and low-dose metronidazole synergistically against Clostridioides difficile infection and recurrence prevention

Clostridioides difficile is an anaerobic, spore-forming, Gram-positive pathogen responsible for various conditions from mild diarrhea to severe toxic megacolon and potentially death. Current treatments for C. difficile infection (CDI) rely on antibiotics like vancomycin and metronidazole (MTZ); however, the high doses required often disrupt gut microbiota, leading to a high recurrence rate. Mitomycin C (MMC), a chemotherapy drug approved by the FDA, is known for inducing phage production in lysogenic bacterial strains, effectively targeting the host bacteria. Given that 70% of C. difficile strains harbor prophages, this study investigates MMCs potential to enhance antibiotic efficacy against CDI. Our in vitro experiments indicate that MMC acts synergistically with MTZ to inhibit the growth of C. difficile strain R20291. Furthermore, this combination decreases biofilm-resident vegetative cell resistance and reduces the MTZ concentration needed to kill C. difficile in stool samples ex vivo. In a CDI mouse relapse model, in vivo results show that MMC combined with a low dose of MTZ significantly improves survival rates and reduces fecal spore counts after antibiotic treatment. Overall, these findings suggest that a low-dose combination of MMC and MTZ offers enhanced therapeutic efficacy for CDI, both in vitro and in vivo, and may provide a promising new approach for treatment.