Antibiotic binding to polytetrafluoroethylene via glucosaminoglycan-keratin luminal coating

Vascular prosthetic graft infection is one of the most catastrophic problems complicating vascular surgery. The purpose of the present study was to determine the efficacy of binding an antibiotic to a vascular prosthesis via a glucosaminoglycan-keratin luminal coating (GKLC). Ten adult mongrel dogs had polytetrafluoroethylene (PTFE) grafts inserted into the right common carotid artery and PTFE grafts with GKLC bonded with cefoxitin inserted into the left common carotid artery. Before the neck incision was closed, an infusion of 1 X 10(8) Staphylococcus aureus was administered intravenously during a 15-minute period to each dog. Grafts were harvested at 10 different time periods (1, 2, 3, 5, 7, 10, 14, 18, 21, and 28 days). At the time of harvesting, cultures were taken of the lumen of each graft. Washout of antibiotic from the graft lumen was determined by measuring zones of inhibition of disks excised from the antibiotic grafts that were placed on S. aureus plates. Results demonstrated that only 1 of the 10 GKLC-cefoxitin grafts was infected compared with 10 of 10 regular PTFE grafts (p less than 0.003). Regression analysis showed antibiotic elution to occur in an exponential fashion (r = 0.9654) with no detectable antibiotic present after 10 days. GKLC with cefoxitin significantly protects the PTFE graft lumen from infection during bacteremia compared with regular PTFE. The role of antibiotic-bound grafts in relation to the use of intravenous antibiotics will need to be determined by further studies.