VANCOMYCIN-LOADED MESH REDUCES STAPHYLOCOCCAL INFECTIONS IN A MURINE EXTENSOR MECHANISM RECONSTRUCTION MODEL WITH MARLEX MESH

Introduction Infection following extensor mechanism reconstruction with Marlex mesh is a devastating and limb threatening complication. The purpose of this study was to evaluate whether vancomycin-loaded mesh reduced staphylococcal infection in a murine extensor mechanism reconstruction model with Marlex mesh. Methods Mouse-sized, eight-layer Marlex mesh constructs were fabricated to simulate clinical reconstruction and soaked in a vancomycin solution (50 mg/mL) for in vitro and in vivo testing. Three methicillin-resistant clinical isolates from human periprosthetic knee infections were evaluated: Staphylococcus aureus, Staphylococcus epidermidis , and Staphylococcus lugdunensis. In vitro testing assessed vancomycin loading, mechanical properties, antibacterial activity, and early biofilm inhibition. For in vivo experiments, plain or vancomycin-loaded Marlex meshes were implanted into the murine extensor mechanism and inoculated intraoperatively (5 per group per isolate). Meshes and surrounding tissues were harvested on postoperative day 9 for quantitative culture. Results For all three isolates, vancomycin-loaded Marlex mesh exhibited sustained antibacterial activity for up to 3 days in vitro based on zone of inhibition testing (days 1–3, p < 0.0001 for each isolate). In vitro testing of biofilm inhibition demonstrated significant reduction in biofilm-associated colony-forming units at 6 hours after inoculation and remained low thereafter (p<0.05 for each isolate). In vivo , vancomycin-loaded Marlex mesh reduced bacterial burden on meshes and surrounding tissues by > 3 log₁₀ compared with plain mesh for all three isolates (p<0.01 for both mesh and tissue for all isolates). Conclusion Vancomycin-loaded Marlex mesh provided sustained local antibacterial activity and significantly reduced staphylococcal infection without compromising mechanical properties in a murine extensor mechanism reconstruction model. This approach may represent a promising adjunct to reduce infection risk in extensor mechanism reconstructions with Marlex mesh after total knee arthroplasty.