title: Antimicrobial activity of platelet-leukocyte gel against Staphylococcus aureus.
abstract: Platelet-leukocyte gel (PLG) contains high concentrations of platelets and leukocytes. As leukocytes play an important role in the innate host-defense, we hypothesized that PLG might have antimicrobial properties. This study investigated the antimicrobial activity of PLG against Staphylococcus aureus and the contribution of myeloperoxidase (MPO), present in leukocytes, in this process. Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were obtained from whole blood of six donors. PLG was prepared by mixing PRP with autologous (PLG-AT) or bovine thrombin (PLG-BT). Antimicrobial activity of PLG-AT, PLG-BT, PRP, and PPP was determined in a bacterial kill assay. MPO release was measured by ELISA and activity was measured using a MPO activity assay. Cultures showed a rapid decrease in the number of bacteria for both PLG-AT and PLG-BT, which was maximal between 4 and 8 h, to approximately 1% of the bacteria in controls. The effect of PLG-AT was largest and significantly different compared to PRP (p = 0.004) and PPP (p < 0.001), however not compared to PLG-BT (p = 0.093). PLG-AT, PLG-BT, and PRP showed a comparable, gradually increasing MPO release. MPO activity was comparable for all groups and remained stable. No correlation between MPO release, activity, and bacterial kill could be found. PLG appears to have potent antimicrobial capacity, but the role of MPO in this activity is questionable. PLG might represent a useful strategy against postoperative infections. However, additional research should elucidate its exact antimicrobial activity.
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Room G05.228, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. d.j.f.moojen@umcutrecht.nl
authors.forename: Dirk Jan F
authors.initials: DJ
authors.lastname: Moojen
authors.forename: Peter A M
authors.initials: PA
authors.lastname: Everts
authors.forename: Rose-Minke
authors.initials: RM
authors.lastname: Schure
authors.forename: Ed P
authors.initials: EP
authors.lastname: Overdevest
authors.forename: André
authors.initials: A
authors.lastname: van Zundert
authors.forename: Johannes T A
authors.initials: JT
authors.lastname: Knape
authors.forename: René M
authors.initials: RM
authors.lastname: Castelein
authors.forename: Laura B
authors.initials: LB
authors.lastname: Creemers
authors.forename: Wouter J A
authors.initials: WJ
authors.lastname: Dhert
mesh_terms: D001770:Blood Bactericidal Activity; D001773:Blood Cells / Q000201:enzymology / Q000502:physiology*; D001792:Blood Platelets / Q000502:physiology*; D015169:Colony Count, Microbial; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005782:Gels; D006801:Humans; D007962:Leukocytes / Q000201:enzymology / Q000502:physiology*; D008297:Male; D009195:Peroxidase / Q000378:metabolism; D013211:Staphylococcus aureus / Q000502:physiology*; D013997:Time Factors
chemical_list: D005782:Gels; D009195:Peroxidase