AN INCREASED CONCENTRATION OF RIFAMPICIN BONDED TO GELATIN-SEALED DACRON REDUCES THE INCIDENCE OF SUBSEQUENT GRAFT INFECTIONS FOLLOWING A STAPHYLOCOCCAL CHALLENGE

The purpose of this study was to determine if 10 mg/ml rifampicin bond ed to gelatin-sealed Dacron (Gelsoft) reduced staphylococcal infection . Grafts soaked in rifampicin were interposed in the left carotid arte ry of 20 merino sheep and then inoculated with 10(8) colony-forming un its of MRSA (10 sheep) or a slime producing Staphylococcus epidermidis (10 sheep). Grafts were harvested at 3 weeks, and perigraft abscess, anastomotic disruption and graft occlusion recorded. Swabs were taken to assess bacterial growth of the perigraft tissues, and external and internal graft surface. Grafts segments were incubated in broth medium , Results were compared with previously published results that used gr aft that were not soaked in rifampicin (control) and grafts soaked in 1.2 mg/ml rifampicin, A total of 4/50 cultures were positive and signi ficantly reduced for S. epidermidis compared with the control group of 30/50 (P < 0.05) and the 1.2 mg/ml group of 13/45 (P < 0.05). For the methicillin resistant staphylococcus aureus (MRSA) group, 6/40 cultur es were positive, which was significantly reduced compared with the co ntrol group (38/40, P < 0.05) and the 1.2-mg/ml group (19/32, P < 0.05 ). In conclusion an increased concentration of rifampicin significantl y reduced the incidence of prosthetic vascular graft infection followi ng a challenge of MRSA or S. epidermidis. (C) 1998 Published by Elsevi er Science Ltd. All rights reserved.