{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T13:11:21Z","timestamp":1765458681024,"version":"3.46.0"},"reference-count":51,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T00:00:00Z","timestamp":1765411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Medical Affairs and Innovation (MAI) of Canadian Blood Services","award":["IG2019-SR"],"award-info":[{"award-number":["IG2019-SR"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Platelet concentrates (PCs) are used to treat patients with platelet deficiencies. PCs are stored at 20\u201324 \u00b0C under agitation for up to 7 days to maintain platelet functionality, but these conditions are amenable for proliferation of contaminants such as Staphylococcus aureus, posing a risk for transfusion-transmitted infections. We investigated the contribution of staphylococcal enterotoxins (SEs) type G (SEG) and type H (SEH) to platelet activation, cytokine release, microRNA (miRNA) modulation, and in vivo virulence. PCs were inoculated with wildtype S. aureus CBS2016-05 or SE-deficient mutants (\u0394seg, \u0394seh, \u0394\u0394segh) and monitored during storage. Flow cytometry revealed progressive elevation of platelet activation markers CD62P and Annexin V in contaminated PCs, with significantly higher expression in wildtype compared to SE-mutant strains. Cytokine profiling demonstrated that SEs modulate pro- and anti-inflammatory mediators, notably CCL2, TGF-\u03b21, IFN-\u03b3, and TNF-\u03b1, implicating SEG in their regulation. Next-generation sequencing and RT-qPCR validation identified transient induction of immune-related microRNAs miR-98-5p, miR-146a-5p, miR-221-3p, miR-320a-3p, with SE-dependent expression patterns. In a silkworm infection model, wildtype S. aureus-contaminated PCs exhibited significantly higher lethality than SE-deficient strains, confirming toxin-mediated virulence. Collectively, these findings reveal that SEs exacerbate platelet activation and immune dysregulation during storage, enhancing bacterial pathogenicity. This study identifies platelet-derived cytokine and miRNA signatures as potential biomarkers of bacterial contamination and underscores the need to mitigate SE-driven platelet dysfunction to improve transfusion safety.<\/jats:p>","DOI":"10.3390\/toxins17120593","type":"journal-article","created":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T12:57:41Z","timestamp":1765457861000},"page":"593","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Staphylococcal Enterotoxins Modulate Platelet Response During Storage of Platelet Concentrates and Impair Silkworm Survival"],"prefix":"10.3390","volume":"17","author":[{"given":"Sylvia Ighem","family":"Chi","sequence":"first","affiliation":[{"name":"Medical Microbiology, Canadian Blood Services, Ottawa, ON K1G 4J5, Canada"},{"name":"Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1G 4J5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chelsea","family":"McGregor","sequence":"additional","affiliation":[{"name":"Research, Canadian Blood Services, Ottawa, ON K1G 4J5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0082-0944","authenticated-orcid":false,"given":"Nicolas","family":"Pineault","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1G 4J5, Canada"},{"name":"Research, Canadian Blood Services, Ottawa, ON K1G 4J5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0705-4987","authenticated-orcid":false,"given":"Sandra","family":"Ramirez-Arcos","sequence":"additional","affiliation":[{"name":"Medical Microbiology, Canadian Blood Services, Ottawa, ON K1G 4J5, Canada"},{"name":"Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1G 4J5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"5","DOI":"10.21037\/aob-24-31","article-title":"Platelet concentrates safety: A focus on the challenging pathogen Staphylococcus aureus\u2014A narrative review","volume":"10","author":"Chi","year":"2025","journal-title":"Ann. 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