Antibacterial Effects of Vascular Grafts Treated with Rifampicin, Colistin, Vancomycin, or Daptomycin

Original Article
Introduction: Some reports suggest that rifampicin treatment of vascular grafts is useful when surgically treating vascular infections and mycotic aneurysms. However, the experimental evidence is limited, and the antibacterial effects of other antibiotic-treated vascular grafts are unknown. Methods: Vascular grafts were immersed in several antibiotic solutions (rifampicin, colistin, vancomycin, or daptomycin). After Pseudomonas aeruginosa PAO1 or Staphylococcus aureus N315 were inoculated into the graft exterior, the number of colony-forming units (CFU) inside and outside the grafts was measured over time. Moreover, bonding of colistin and vancomycin to the grafts was quantified. Results: For grafts immersed in rifampicin, the CFU values outside the grafts decreased over time and those inside the grafts did not increase when the grafts were exposed to a 106 CFU/mL concentration of PAO1 or N315. However, at 108 CFU/mL, the CFU values increased over time outside and inside the grafts. In PAO1 testing, grafts treated with colistin resisted pathogens in the tested area, and grafts treated with both colistin and rifampicin had even greater resistance. In N315 testing, vancomycin-treated grafts had some resistance to infection, but daptomycin-treated grafts did not. The bonding of colistin and vancomycin to the grafts depended on the immersion time. Conclusions: Rifampicin-bonded grafts have a strong antibacterial effect when the concentrations of pathogens are low. Colistin-bonded grafts are effective against P. aeruginosa infection, and vancomycin-bonded grafts are effective against S. aureus infection.