In vitro evaluation of the antimicrobial efficacy of a new silver-triclosan vs a silver collagen-coated polyester vascular graft against methicillin-resistant Staphylococcus aureus

Objectives: Vascular graft infection is a rare but serious complication of vascular reconstructive surgery. This in vitro study investigated the antimicrobial efficacy of a new, silver-triclosan collagen-coated polyester vascular graft compared with a silver collagen-coated polyester vascular graft alone during the first 24 hours. Methods: The antimicrobial efficacy of the investigated vascular grafts was assessed by performing a time-kill kinetic assay following Clinical and Laboratory Institute Standards-approved guidelines M26-A. For the purpose of the experimental study, the ATCC 33591 strain of methicillin-resistant Staphylococcus aureus (American Type Culture Collection, Manassas, Va) was used. All assays were repeated sixfold. Bacterial survival numbers were obtained at 1, 4, 8, 12, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log(10) reduction factor (logRF), according to the approved guideline M26-A. Results: Both antimicrobial vascular grafts achieved >3 logRF and fulfilled the efficacy criterion for bactericidal activity but performed differently in their speed of antimicrobial action. The silver-triclosan vascular graft achieved 3.37 logRF after 8 hours, and the silver vascular graft showed a 4.19 logRF after 24 hours. The silver-triclosan graft yielded significantly lower colony-forming units/mL counts after 4 hours compared with the silver graft (4.29 x 10(4) vs 1.03 x 10(6); P = .031). Conclusions: Both antimicrobial collagen-coated polymer vascular grafts showed bactericidal activity against methicillin-resistant Staphylococcus aureus in vitro. Although the silver-triclosan vascular graft showed a faster antimicrobial efficacy, the silver graft exhibited its antimicrobial properties after 24 hours. Which concept will protect an implanted vascular prosthetic graft better from bacterial contamination and subsequent infection needs to be investigated further in in vivo animal and clinical studies. (J Vasc Surg 2012; 55: 823-9.) Clinical Relevance: Vascular graft infection is a rare but one of the most serious complications of vascular reconstructive surgery. Conservative treatment of prosthetic graft infections is rarely successful and is used only in patients with a high operative risk or apparently limited infection. The most pre-eminent strategy against this severe complication therefore is primary prevention of vascular graft infection. The use of antimicrobial vascular grafts might support prevention of vascular graft infection. Results of a standardized experimental study on the antimicrobial efficacy of the silver-triclosan collagen polyester vascular graft with an identical collagen polyester vascular graft containing silver alone are presented.