Antimicrobial activity of blood-derived biomaterials against different biofilm-forming bacteria strains commonly found in wounds

Platelet-Rich Plasma (PRP) and Leucocytes-PRP (L-PRP) are blood products widely used to promote wound healing that have also shown antimicrobial activity. The aim of the study was to perform a systematic review of the literature on the contribution of leucocytes included in PRP preparations in terms of their antimicrobial properties and to conduct in vitro studies to explore the antimicrobial properties of blood products against free bacteria and bacteria-forming biofilm. Assays included growth kinetics and crystal violet biofilm formation assays. The systematic review revealed that the limited numbers of studies so far conducted did not allow determination of the specific contribution of leucocytes to the bactericidal effect of PRP preparations. However, overall, PRP preparations do demonstrate bacteriostatic properties against the majority of the bacterial strains tested in the literature. From the in vitro studies carried out here the only preparation showing growth control of Staphylococcus aureus was the L-PRP preparation, where the leukocyte and neutrophil content of the preparation both significantly influenced bacterial growth kinetics. PRP and PPP (Platelet Poor Plasma) preparations significantly reduced Pseudomonas and Acinetobacter growth over a 12-hour period. Against the Gram-negative bacteria, all the biomaterials tested gave a reduced level of biofilm biomass formation.