Abstract: Objective To investigate the inhibitory efficacy of platelet-rich plasma (PRP) in frozen and lyophilized forms against four common infectious bacteria and to compare the differences in inhibition. Methods Fresh platelets from healthy volunteers were collected by blood apheresis machine and prepared into frozen PRP and lyophilized PRP, which as experimental groups. We set saline as control group and observed whether above 3 groups could inhibit the growth of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Candida albicans (C. albicans) and Pseudomonas aeruginosa (P. aeruginosa) at different time points by coated plate counting method. Results Compared to saline group, both frozen PRP and lyophilized PRP groups inhibited the growth of S. aureus, E. coli and C. albicans, and increased P. aeruginosa growth. At each point, frozen PRP and lyophilized PRP groups showed significant inhibitory effects against S. aureus, E. coli and C. albicans. There were significant differences in bacteriostasis at some points between the frozen PRP and lyophilized PRP groups. Conclusion Both frozen PRP and lyophilized PRP have antibacterial effects with specific antibacterial spectrum and timeliness, and lyophilized PRP has stronger effects than frozen PRP.

Key words: Platelet-rich plasma, Frozen, Lyophilized, Bacteriostatic test