The Addition of Lysostaphin Dramatically Improves Survival, Protects Porcine Biomesh from Infection, and Improves Graft Tensile Shear Strength

BackgroundLysostaphin (LS), a naturally occurring Staphylococcal endopeptidase, has the ability to penetrate biofilm, and has been identified as a potential antimicrobial to prevent mesh infection. The goals of this study were to determine if LS adhered to porcine mesh (PM) can impact host survival, reduce the risk of long-term PM infection, and to analyze lysostaphin bound PM (LS-PM) mesh-fascial interface in an infected field.MethodsAbdominal onlay PMs measuring 3 × 3 cm were implanted in select groups of rats (n = 75). Group assignments were based on bacterial inoculum and presence of LS on mesh. Explantation occurred at 60 d. Bacterial growth and mesh-fascial interface tensile strength were analyzed. Standard statistical analysis was performed.ResultsOnly one out of 30 rats with bacterial inoculum not treated with LS survived. All 30 LS treated rats survived and had normal appearing mesh, including 20 rats with a bacterial inoculum (106 and 108 CFU). Mean tensile strength for controls and LS and no inoculum samples was 3.47 ± 0.86N versus 5.0 ± 1.0N (P = 0.008). LS groups inoculated with 106 and 108 CFU exhibited mean tensile strengths of 4.9 ± 1.5 N and 6.7 ± 1.6 N, respectively (P = 0.019 and P < 0.001 compared with controls).ConclusionRats inoculated with S. aureus and not treated with LS had a mortality of 97%. By comparison, LS treated animals completely cleared S. aureus when challenged with bacterial concentrations of 1 × 106 and 1 × 108 with maintenance of mesh integrity at 60 d. These findings strongly suggest the clinical use of LS-treated porcine mesh in contaminated fields may translate into more durable hernia repair.