Late hematogenous infection of subcutaneous implants in rats

Late biomaterial-centered infection is a major complication associated with the use of biomaterial implants. In this study biomaterials that had been implanted subcutaneously in rats were hematogenously challenged with bacter ia 4 weeks after implantation. Bacteria were spread either by intravenous i njection or by stimulation of bacterial translocation. It was found that no ne of the biomaterials was infected by hematogenous spread, whereas 5% of t he implants were infected by perioperative contamination. We conclude that late hematogenous infection of subcutaneous biomaterials does not occur in the rat. For humans as well, there are growing doubts whether implants actu ally become infected through hematogenous routes; it is thought that late i nfections may be caused by delayed appearance of perioperatively introduced bacteria.