Comparison of the antibacterial properties of Mg, Mg-2Ag, and Ti intramedullary implants in a murine model of Staphylococcus aureus bacteremia -related periprosthetic osteomyelitis

Abstract

Knowledge on the susceptibility of novel biomaterials to potential challenges in clinical practice is critical to defining the scope of implementation and further improvement of candidate materials. While periprosthetic infections remain a major and most difficult to treat complication in implantation orthopedics, magnesium-based biodegradable alloys are currently under eager attention as alternatives. Many in vitro studies reported profound antibacterial potential of pure magnesium and its alloys with improved bactericidal features. Some animal models with direct inoculation of bacteria or implantation of infected implants confirmed these results in vivo. However, the susceptibility of magnesium and binary alloys of magnesium and silver has not previously been assessed in experimental settings for hematogenous periprosthetic osteomyelitis. In the present study, we compared the antibacterial activity of pure Mg and Mg-2Ag with that of medical grade Titanium using a murine model for Staphylococcus aureus bacteremia –related peri-implant bone infection. The bacteria colonization was inhibited on surfaces of Mg and Mg-2Ag intramedullary implants. However, the bacteria load in surrounding tissue was found to be similar between the three materials. Current findings (i) indicate that biocidal efficacy of a material in vivo can be influenced by contamination route; (ii) aware of a limited antibacterial potential of unmodified magnesium and magnesium-silver implants for patients with elevated risks of bloodstream infections; and (iii) emphasize the need of further improvements/alloy modifications for particular clinical purposes.