Proof of concept for detection of staphylococcal enterotoxins in platelet concentrates as a novel safety mitigation strategy

Background and Objectives Staphylococcus aureus is a predominant contaminant of platelet concentrates (PCs) that can evade detection during screening with culture methods. Importantly, S. aureus produces staphylococcal enterotoxins (SEs) during PC storage, which are linked to slow growth and enhanced biofilm formation. This study investigated timing of SE production during PC storage and feasibility of SE detection as a PC safety strategy. Materials and Methods Genomic and transcriptomic data of transfusion‐relevant S. aureus PS/BAC/169/17/W, PS/BAC/317/16/W, CI/BAC/25/13/W and CBS2016‐05 were used to determine the presence and differential expression of exotoxin genes in PCs. Trypticase soy broth (TSB) and PCs were inoculated with 1.0E+06 cfu/mL of S. aureus PS/BAC/169/17/W and CBS2016‐05. Expression of SEs at different growth phases was confirmed with Western blotting. PCs were inoculated with 30 cfu/unit of the same strains, and SE detection during PC storage was optimized with a sandwich dot‐ELISA assay. Results S. aureus genomes contain multiple exotoxin genes including those encoding for SEs. Transcriptome data revealed significant upregulation (0.5–6.7‐fold, p