Bacteriostatic effect of equine pure platelet-rich plasma and other blood products against methicillin-sensitive Staphylococcus aureus. An in vitro study.

This research study evaluates the bacteria-inhibiting effects of various equine blood products on a common strain of bacteria, methicillin-sensitive Staphylococcus aureus (MSSA), in a laboratory setting. Additionally, it examines the decay of specific factors in these blood products and looks for correlations between platelet counts, leukocyte counts, and the growth of MSSA.

Study Background

• The purpose of the study was to investigate the bacteriostatic effect (growth inhibiting effect) of five different blood products (Pure Platelet-Rich Plasma, also known as P-PRP; Pure Platelet-Rich Gel, also known as P-PRG; Leukocyte-Poor Gel, also known as LPG; Platelet-Poor Plasma, also PPP, and Heat Inactivated Plasma, also called IP) on a strain of bacteria that is sensitive to antibiotics, specifically, MSSA.
• These blood products were studied in an “in vitro” setting, meaning they were studied outside of a living organism in a controlled environment.

Methodology

• The researchers used blood components which were obtained from fourteen horses via a manual protocol.
• These components were combined with the MSSA bacteria and Müller-Hinton Broth (a type of nutrient-rich solution in which bacteria can grow), then cultured in an environment maintained at a temperature of 37°C for a full day (24 hours).
• Sampling was conducted at one, four, eight, twelve, and twenty-four hours to determine bacterial growth (measured in colony-forming units) as well as concentrations of Platelet Factor 4 (PF-4), Transforming Growth Factor Beta 1 (TGF-β1), and Platelet-Derived Growth Factor BB (PDGF-BB).

Results and Conclusions

• The results showed significant inhibition of bacterial growth in P-PRP, P-PRG, LPG, and PPP in comparison with IP and a control group in the initial 12 hours.
• The P-PRG variant maintained higher levels of TGF-β1 and PDGF-BB over time, compared to the other blood component variants.
• The researchers concluded that the plasma complement (a part of the immune system existing in blood that helps, or complements, the immune system to destroy pathogens) could play a significant role in the bacteriostatic effects of these blood products on MSSA.
• Particularly, P-PRG stood out as the superior biomaterial because it not only showed a substantial bacteriostatic effect but also demonstrated the highest concentration of growth factors.