The Effect of Vancomycin and Silver Combination on the Duration of Antibacterial Activity of Bone Cement and Methicillin-Resistant Staphylococcus aureusBiofilm Formation

Background.Local prevention of periprosthetic infection and treatment of infectious complications after various joints arthroplasties includes the use of polymethylmethacrylate-based spacers impregnated with antimicrobial agents. At the same time, the added components are able to change the bone cement characteristics and have variable antimicrobial effect duration. The aim of the studywas to evaluate the duration of antimicrobial activity and the effect on the MRSA ATCC 43300 biofilm formation on bone cement samples with gentamycin impregnated with vancomycin and/or highly dispersed silver.Materials and Methods.Samples were made from bone cement DePuy CMW 1 Gentamicin and mixed with vancomycin and/or highly dispersed silver. The elemental composition was studied by scanning electron microscopy and micro-x-ray spectral analysis. The study of the antimicrobial activity duration was performed by daily applying an incubation solution with samples to the bacterial lawn surface. The effect on biofilm formation was evaluated by immersing the test samples in LB-broth with MRSA.Results.The control samples did not have antimicrobial activity (AMA) against MRSA ATCC 43300. Test samples, additionally containing 10 wt.% of vancomycin was effective for 9 days. When adding highly dispersed silver, the lengthening of the samples activity time was recorded. So, when applying 2.5 wt.% of highly dispersed silver, the duration of AMA was 21 days, and when increased to 10 wt.% — 34 days. Energydispersion analysis of the sample surface with 10 wt.% of vancomycin and highly dispersed silver showed that the skeletal structure type contains matrix component based on barium sulfate with silver inclusions. During the study of the samples effect on a typical strain biofilm formation, no statistically significant differences were found between the optical density of gentian violet extracts in the negative control and in the medium with MRSA.Conclusion. The vancomycin with highly dispersed silver combination prolonged the antimicrobial activity of the samples against MRSA ATCC 43300 and effectively prevented the formation of microbial biofilms on its surface. Despite the fact that the conditions of the conducted experiment in vitro are not identical to the conditions of bone cement antimicrobial spacers clinical use, our results indicate the need to use spacers with a known duration of antimicrobial activity and to comply with the terms of temporary structures replacement.