Antibiotic Efficacy againstStaphylococcus epidermidisAdherent to Vascular Grafts

Antibiotic bonded grafts may improve the treatment results of vascular graft infections. The purpose of this study was to determine the antibiotic and antibiotic concentration needed to be effective againstStaphylococcus epidermidis-infected vascular grafts. The efficacy of four antibiotics (minocycline, cefazolin, vancomycin, and rifampin) againstS. epidermidisadherent to Dacron or Teflon vascular grafts was studiedin vitro.Kill kinetic studies were performed with 18 and 42 hr of exposure of Dacron-adherent and Teflon-adherentS. epidermidisat 1, 4, 16, and 64 times the minimum inhibitory concentration (MIC) of each antibiotic. Antibiotic efficacy against graft-adherentS. epidermidisat 42 hr was best at concentrations 64× MIC for minocycline, cefazolin, and vancomycin and 4× MIC for rifampin. None of the antibiotics totally eradicated the graft-adherent bacteria. Antibiotics were equally effective forS. epidermidisadherent to Dacron and Teflon grafts. Antibiotic concentrations several times that predicted by the MIC were needed for all antibiotics to achieve significant killing of graft-adherent bacteria, with rifampin the most effective at the lowest concentration.