Efficacy of local rifampin/minocycline delivery (AIGIS(RX)®) to eliminate biofilm formation on implanted pacing devices in a rabbit model.

PURPOSE: Device-related infections represent a significant clinical challenge. Once established, these infections prove difficult to treat with existing antibiotic regimens, compromising the health of device recipients, and usually requiring surgical intervention to resolve. The purpose of this study was to determine the ability of the AIGIS(RX)® Anti-Bacterial envelope to reduce the formation of bacterial biofilm on implanted pacing devices. METHODS: An infection was established in a rabbit model by creating bilateral subcutaneous implant pockets, into which a pacing device with or without AIGIS(RX)® was placed. The incisions were closed, and a defined dose of bacteria was infused into each implant pocket. After seven days, devices were explanted and assessed for viable bacteria by a sonication/vortex procedure to quantify bacteria, and by imaging of the device surface by scanning electron microscopy and laser scanning confocal microscopy. RESULTS: The presence of the AIGIS(RX)® envelope eliminated recoverable, viable bacteria from the explanted devices using a vortex/sonication technique from in vivo models of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus capitis, and Escherichia coli infections. Scanning electron microscopy and confocal microscopy demonstrate greatly reduced biological material on the pacemaker surfaces in the presence of the AIGIS(RX)® envelope compared to untreated controls. CONCLUSION: These results demonstrate that in this animal model, the AIGIS(RX)® device reduces the formation of adherent bacteria and reduces bioburden on implanted, infected pacemaker devices.

Inhibition of Staphylococcus aureus biofilms by a novel antibacterial envelope for use with implantable cardiac devices.

Biofilm formation on representative implantable medical devices using a known human pathogen (Staphylococcus aureus) was significantly reduced (p < 0.01) at all time points measured (24,48, and 72 hours) by employing a novel antibacterial envelope (AIGIS Rx). The result was demonstrated using a standard US Centers for Disease Control (CDC) bioreactor model and the results were confirmed by Scanning Electron Microscopy (SEM). The antibacterial envelope used in the study is coated with a proprietary combination broad spectrum antibiotics (rifampin and minocycline) embedded in a resorbable polymeric coating. The antibiotics are designed to elute out of the coating over a multi-day period for controlled, site-specific drug delivery. The infection rate for patients receiving pacemakers and defibrillators is increasing faster than the rate of new implants and the growing resistance of S. aureus strains suggests that conventional, systemic antibiotic prophylaxis may have limited future utility. Moreover, emerging evidence suggests that bacterial biofilms result in infections of implantable medical devices. These findings demonstrate the in vitro efficacy of a new means to address potential biofilm-derived Hospital Acquired Infections (HAIs) related to implantable medical devices composed of titanium inclusive of pacemakers and defibrillators by means of a locally delivered, low dose, combination antibacterial treatment.