Sustained-release vancomycin sheet may help to prevent prosthetic graft methicillin-resistant Staphylococcus aureus infection.

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of a sustained-release sheet with vancomycin (VCM) to prevent prosthetic graft infection. METHODS: VCM was incorporated into a poly-L-lactide-co-caprolactone (PLCA) sheet (VCM-PLCA). The release profile of VCM from the VCM-PLCA sheet and the tissue concentration of VCM released in vivo were examined. To assess the antibacterial effect of the VCM-PLCA sheet, a sterile Dacron sheet was implanted into 96 male mice (C57BL/6), who were randomly divided into four groups of 24 each and treated as follows no treatment (group A, control group), a local bolus injection of an aqueous solution of VCM (group B), a plain PLCA sheet (group C), and a VCM-PLCA sheet (group D). After the treatment, methicillin-resistant Staphylococcus aureus (MRSA) (1 x 10(6) colony forming units) was inoculated onto the Dacron graft surface. The Dacron grafts were retrieved on days 3, 7, 10, and 14 after the implantation, and the number of MRSA in the Dacron grafts was counted. RESULTS: VCM was slowly released from the VCM-PLCA sheet over 2 weeks in vivo, and the mean in vivo concentrations of VCM in the tissue around a VCM-PLCA sheet were 7.95, 26.39, 13.87, 12.51, 8.36, and 10.33 mug/mL (the minimum inhibitory concentration of VCM against MRSA is 2.0 mug/ml), at 1, 2, 5, 7, 10, and 14 days after the implantation, respectively. MRSA colonization on the cultivated agar plates was detected in all samples from groups A, B, and C at any postoperative time points. In contrast, some samples were negative for bacterial cultures in group D (2, 3, 1, and 2 samples out of 6 samples each on days 3, 7, 10, and 14 after the implantation, respectively). At all time points, the number of MRSA bacteria in the implanted Dacron graft in group D was by far the lowest (P < .01 at each time point). CONCLUSIONS: The sustained-release sheet with VCM appears to be effective for the reduction of subcutaneous prosthetic graft infection.