Prevention of Staphylococcus aureus graft infection by a new gelatin-sealed vascular graft prebonded with antibiotics

ObjectiveThe aim of this study was to evaluate the efficacy of a new gelatin-sealed graft prebonded with two antibiotics in resisting infection with Staphylococcus aureus (S aureus) A980142 after direct bacterial application in a dog model.MethodsTwelve 6.0-mm polyester grafts were implanted in dogs end-to-end into the infrarenal aorta. The dogs were divided into two groups. A test group (n = 6) received experimental antibiotic-bonded gelatin-sealed knitted polyester grafts, loaded with two antibiotics, rifampin and tobramycin. A control group (n = 6) received commercial gelatin-sealed knitted polyester grafts. At the end of graft implantation, 50 μl of a 1.8 × 104 CFU/mL S aureus solution were instilled directly over the graft. One week after implantation, grafts were harvested with sterile technique. Quantitative cultures were obtained from all the harvested grafts. The results were expressed as colony-forming units per cm2 of surface of the graft. Bacteriological study was also performed on various tissue samples. The χ2 test was used to compare the culture proven infection of control and antibiotics-bonded grafts.ResultsMean inoculum size was similar in the two groups of dogs. Five of the six control grafts grew S aureus A980142 at the time of graft removal, whereas none of the six antibiotic-bonded gelatin-sealed grafts were infected (P = .0192). None of the organ samples were infected in the group implanted with antibiotic-bonded grafts, whereas 15/34 samples grew S. aureus in the control group.ConclusionThese results indicate that this gelatin sealed graft prebonded with two antibiotics resists infection caused by S aureus graft contamination in a dog model.

Clinical relevanceGraft infection remains a crucial problem in vascular surgery, even if its occurrence is rare. Several authors have proposed the use of antibiotic-bonded grafts to prevent or to treat graft infections. Development of grafts that are resistant to infection has considerable appeal, but, until now, none is commercially available. We used a dog model to evaluate the resistance to infection of a new gelatin-sealed graft manufactured prebonded with two antibiotics, rifampin and tobramycin. In this study, we demonstrate that this prebonded graft resists to infection caused by local contamination with Staphylococcus aureus. Further studies are required to confirm our experimental findings.