Prevention of perioperative vascular prosthetic infection with a novel triple antimicrobial-bonded arterial graft

Abstract

Previously, we investigated a locally developed technique of bonding arterial grafts with three antimicrobials to protect against early (within 2weeks) perioperative bacterial contamination encountered occasionally during aortic graft prosthetic reconstruction. Vascular graft infections are classified by their appearance time (early [<4months] vs late [>4months] after graft implantation), degree of incorporation into the surrounding vessel wall, connectivity to the postoperative wound, and extent of graft involvement. In the current phase of testing, we evaluated the ability of our novel triple antimicrobial-bonded graft to prevent infection in the first 8weeks after implantation. In nine Sinclair miniature pigs, we surgically implanted a 6-mm vascular Dacron patch graft in the infrarenal abdominal aorta. Five pigs received grafts chemically bonded with a 60-mg/mL solution of rifampin, minocycline, and chlorhexidine, and four pigs received unbonded grafts. Before implantation, the five bonded grafts and three of the unbonded grafts were immersed for 15minutes in a 2-mL solution containing 1-2× 107colony-forming units (CFUs)/mL of Staphylococcus aureus (ATCC 29213); the fourth unbonded graft served as a control. At week 9, all of the grafts were explanted. All S aureus-inoculated bonded grafts (n= 5) showed no bacterial growth. The unbonded, uninoculated graft (n= 1) showed low-level bacterial growth (<1.2× 103CFUs); S cohnii spp urealyticus, but not S aureus, was isolated, which suggested accidental direct perioperative contamination. Two pigs that received S aureus-inoculated, unbonded grafts were euthanized because of severe S aureus infection (<6.56× 108CFUs per graft). Results of histopathologic analysis were concordant with the microbiologic findings. Most intergroup differences were observed in the inflammatory infiltrate in the aortic wall at the site of graft implantation. In all pigs that received bonded grafts, Gram staining showed no bacteria. Our triple-bonded aortic graft prevented perioperative aortic graft infection for at least 8weeks in a porcine model. The synergistic antimicrobial activity of this graft was sufficient to prevent and/or eradicate infection during that period. Further studies are needed to assess the graft's ability to combat early-onset vascular graft infection for up to 4months.