Effect of Equine Leukocyte-Reduced Platelet Concentrates on Methicillin-Resistant Staphylococcus aureus Cultures and Measurement of Temporal Growth Factor Degradation

The aims of this study were (1) to evaluate the antibacterial effects of equine platelet concentrates (PCs) and other blood-derived preparations on methicillin-resistant Staphylococcus aureus (MRSA); (2) to determine the effect of MRSA on the concentration of transforming growth factor beta 1 and platelet-derived growth factor BB over time; and (3) to determine the correlations between MRSA growth and blood cell counts (platelets and leukocytes), as well as growth factor (GF) concentrations, in PCs and other blood-derived preparations. Blood from 14 clinically healthy horses was used to prepare the different blood-derived preparations. Bacterial growth was significantly inhibited by the different PCs and the cell-free plasma products, mainly during the first 8 hours. Growth factor concentrations were not significantly affected by the presence of bacteria. No correlation between MRSA growth inhibition and blood cells and/or GFs was found. The in vitro bacteriostatic effect of PCs on MRSA could be predominantly attributed to the plasma complement.