Comparison of Antibiotic-Coated versus Uncoated Porcine Dermal Matrix.

Background: The objective of this study was to evaluate the antimicrobial performance of a rifampin/minocycline-coated, non-cross-linked, acellular porcine dermal matrix (XenMatrix AB) compared to an uncoated, non-cross-linked, acellular porcine dermal matrix (Strattice) after implantation/inoculation with methicillin-resistant Staphylococcus aureus or Escherichia coli in a dorsal rabbit model.

Methods: Forty male New Zealand White rabbits were bilaterally implanted with XenMatrix AB or Strattice grafts and inoculated with clinically isolated methicillin-resistant S. aureus (5 × 10 colony-forming units/ml) or E. coli (1 × 10 colony-forming units/ml). At 2 and 8 weeks, sites were analyzed for viable methicillin-resistant S. aureus/E. coli colony-forming units, abscess formation, and histologic response (n = 5 rabbits per group per bacterium per time point).

Results: XenMatrix AB completely inhibited bacterial colonization of the graft, inhibited abscess formation, reduced inflammation and encapsulation, and improved neovascularization compared with Strattice. XenMatrix AB implants exhibited significantly fewer colony-forming units compared with Strattice implants at 2 weeks (methicillin-resistant S. aureus) (p < 0.01) and at 2 and 8 weeks (E. coli) (p < 0.05). In addition, XenMatrix AB implants demonstrated a significantly lower abscess score at 2 weeks (methicillin-resistant S. aureus) and 8 weeks (E. coli) (p < 0.01 in both cases). For both types of bacteria and both time points evaluated, XenMatrix AB implants exhibited minimal inflammation and encapsulation and a lack of neutrophils. In contrast, Strattice implants displayed marked inflammatory and neutrophilic responses and moderate encapsulation.

Conclusions: This study demonstrated the antimicrobial performance of a rifampin/minocycline-coated bioprosthetic (XenMatrix AB) in a rabbit inoculation model. XenMatrix AB completely inhibited bacterial colonization of the graft, with minimal host inflammation and encapsulation, and improved neovascularization compared with Strattice.