Bridging the gap in AMR research: validation of a standardized Galleria mellonella model to evaluate Clostridioides difficile pathogenesis and treatment efficacy

Background: to study CDI pathogenesis and treatment. Methods: ribotypes (RT) and vancomycin treatment. Bacterial burden was quantified via qPCR, and survival was analyzed using Kaplan-Meier curves. Results: CFU/mL in fresh larvae (<7 days since receipt) at 37 °C proved optimal. Fresh larvae exhibited significantly higher survival compared to older larvae (P = 0.003). Infection with toxigenic strains resulted in significantly lower survival (35%) compared to uninfected controls (90%; P < 0.001), with virulence varying significantly among RTs. Vancomycin treatment improved survival to 90% in a dose-dependent manner compared to untreated controls (P < 0.001), with a corresponding reduction in bacterial burden confirmed by qPCR. Conclusion: assays and mammalian studies for future drug development.