34th Annual Scientific Meeting proceedings

Objectives:

Besides hemostasis, platelets provide wound healing and antimicrobial properties. Factors affecting the effectiveness of platelet products may include the manufacturing process, platelet concentration, leukocyte content, platelet activation, and pooling of individual donors.

Methods:

Blood was collected from 6 dogs. Platelet-rich plasma was produced using centrifugation methods, leukocyte-rich and leukocyte-reduced. Platelet lysate (PL) was generated through freeze-thaw cycles. A portion of samples underwent plasma depletion and/or heat treatment. Treatment groups were tested against bacterial strains via bacteria spiking assay at 3 and 24 hours and a 24-hour growth curve assay with 20% and 80% treatment concentrations, which included samples with oxacillin or amikacin.

Results:

The log reduction of Staphylococcus aureus and Escherichia coli was greater with PL compared to broth after 3 hours (p=0.0027 and p=0.0486). Plasma depletion led to a weaker log reduction of Staphylococcus pseudintermedius (p=0.0478) and an improved log reduction for Enterococcus faecalis (p = 0.0396) after 3 hours. Heat treatment led to a weaker log reduction for Enterococcus faecalis after 24 hours (p=0.0026). Leukocyte concentration made no difference. PL suppressed the growth of Staphylococcus aureus best at 20% and Staphylococcus pseudintermedius best at 80%. PL appeared synergistic with amikacin against Staphylococcus aureus, but the effectiveness of oxacillin decreased.

Conclusions:

PL has antimicrobial effects. For the most efficacious product, the manufacturing, dose, and plasma content may need to be tailored to the targeted bacteria. PL showed synergism with amikacin but not oxacillin. Further research is warranted to evaluate the optimal use of PL as an antimicrobial.