Utility of Kirschner Wires as Prosthetic Implants to Investigate Establishment and Treatment of Biofilm-Associated Infections in a Galleria mellonella Model

Objectives Bacteriophage (phage) therapy is being explored as a strategy for clinical control of periprosthetic joint infections, addressing the challenges of antibiotic-resistant bacteria and limitations around the complete eradication of methicillin-resistant Staphylococcus aureus biofilms by conventional antibiotic treatment. Additionally, phage-antibiotic combinations may enhance treatment success through synergistic interactions. This study aimed to compare the efficacy of phage Silviavirus remus (Remus) and vancomycin, independently and together, against S. aureus biofilms on Kirschner-wire (K-wire) implants using Galleria mellonella as an in vivo model, and to assess the biocompatibility of K-wire implantation.

Survival of G. mellonella larvae implanted with S. aureus biofilms and treated with Remus (∼3 × 104 PFU/worm) and/or vancomycin (5 µg/worm) after 72 hours was assessed using Kaplan-Meier curves. Statistical analyses among treatment groups were performed using log-rank tests at p-value < 0.10. Implantation of uncolonized K-wires with treatment administration did not affect survival (100%). Compared with untreated biofilm-infected larvae (77%), vancomycin alone (97%; p = 0.023) or in combination with Remus (93%; p = 0.087) improved survival, whereas Remus alone did not increase survival (67%, p = 0.33). Scanning electron microscopy confirmed the presence of biofilm-associated attachment of S. aureus on K-wires, although adherence was non-uniform. Competing Interest Statement T.A., T.J.L., N.T., S.S.T., and B.W.M.C. are employed by Cytophage Technologies Inc. Footnotes natasha{at}cytophage.com deborah.court{at}umanitoba.ca steven{at}cytophage.com Abbreviations - CFU - colony-forming-units - K-wires - Kirschner wires - MRSA - methicillin-resistant Staphylococcus aureus - PBS - phosphate-buffered saline - PFU - plaque-forming-units - PJIs - Periprosthetic joint infections - SEM - scanning electron microscopy - SM - saline-magnesium buffer - TSA - Tryptic Soy agar - TSB - Tryptic Soy broth