Microvascular Graft Infection in the Rat

Three modes of exposure of PTFE grafts to Staphylococcus aureus strain 763 were compared. It was found that contamination with bacterial suspension containing 108 CFU/ml either before graft implantation or in situ following implantation invariably resulted in graft infection, as revealed by bacterial colonization. Furthermore, the efficiency of these procedures was evident from lack of patency of the infected grafts. When reducing the bacterial concentration to 105 or 103 CFU/ml lower rates of graft infection were noted. Intravenous administration seemed somewhat less effective for establishing graft infection. Finally, our experiment showed a lower resistance to bacterial challenge of microvascular PTFE grafts at implantation than at one week later.