Abstract 2531: Less Invasive but More Effective Method to Prevent Methicillin-Resistant Staphylococcus Aureus (MRSA) Graft Infection by Using Local Sustained Release of Vancomycin (VCM)
Introduction : MRSA graft infection is one of the most serious complications after vascular surgery because its mortality rate is exceedingly high. VCM is a potent antibiotic to MRSA; however, systemic and repeated administration of VCM is not so effective in MRSA graft infection because the tissue concentration of VCM around the graft may be quite low, and often causes serious side effect. To maintain effective tissue concentration of VCM around the prosthetic graft is thus highly desirable to prevent MRSA graft infection.
Hypothesis: A local sustained-release of VCM is effective to prevent murine abdominal aortic graft infection model with MRSA without elevation of blood VCM concentration.
Methods : We have developed poly-L-lactide-co-caprolactone (PLCA) sheet that enabled sustained release of VCM for 2 weeks. Abdominal aorta of a rat was incised and an e-PTFE vascular graft patch (1.5 mm2) was sutured at the anterior wall of the incised aorta. MRSA (1.0±103 colony forming units; CFU) was inoculated onto the graft surface. Thereafter, the graft was treated as follows (n=6 each): no treatment (Control group), an aqueous solution of VCM (5mg, VCM/solution group), PLCA-containing VCM (5mg, VCM/PLCA group). Seven days after the operation, the graft and arterial blood were sampled and cultured to count MRSA cells.
Results : (table⇓) The MRSA count in the graft of VCM/PLCA group were significantly lower than those of the other groups. Blood cultures of VCM/PLCA group were all negative, whereas those of the other groups were all positive. The survival rate in VCM/PLCA group at 28days was higher than Control group.
Conclusion : A local sustained-release sheet incorporating VCM reduced MRSA in the infected vascular graft, prevented sepsis, and drastically improved survival without elevating blood VCM level. This method may develop more effective but less invasive adjuvant for prevention of prosthetic MRSA graft infection.