Prevention of vascular graft infection by rifampin bonding to a gelatin-sealed Dacron graft.

This study examines the efficacy of rifampin bonding to a gelatin-sealed knitted Dacron graft to prevent perioperative bacteremic vascular graft infection. Antibiotic bonding was obtained by soaking grafts for 15 minutes in a 1 mg/ml saline solution of rifampin at 37 degrees C. Nineteen dogs had thoracoabdominal aortic bypass: seven (group I) received a rifampin treated graft; six (group II) received an untreated gelatin-coated graft; and six (group III) received an uncoated Dacron graft. Two days later bacteremic challenge was produced by rapid intravenous injection of 5 x 10(5) colony forming units of methicillin resistant Staphylococcus aureus. Grafts were harvested five days after this challenge and cut into 10 fragments, each submitted to bacterial counts. Results were expressed as CFU/cm2 of graft material. In group I, no graft was infected, whereas all grafts in groups II and III were infected (p less than 0.05). Median bacterial counts from the infected fragments (median +/- SD) were similar in groups II (2.5 x 10(5) CFU/cm2) and III (4 x 10(4) CFU/cm2). Blood cultures at time of sacrifice were negative in all dogs in group I and positive in five of six dogs in groups II and III. Cultures of liver, spleen, kidney, and lung specimens were always negative in group I and positive in 22 of 24 specimens in group II and 23 of 24 specimens in group III. Soaking a gelatin-sealed Dacron graft in rifampin solution evidently prevents early bacteremic graft infection and secondary foci of infection in this model.