The antibacterial and therapeutic effects of equine regenerative medicine on bacterial pathogens A systematic review and meta-analysis

<b>Background:</b> Equine regenerative medicine modalities—including platelet‑rich plasma (PRP), mesenchymal stromal cells (MSCs), and their derivatives—are increasingly explored for their dual roles in antimicrobial activity against equine bacterial pathogens. However, the efficacy and consistency of these therapies remain unclear.<br><b>Objectives:</b> To systematically review and quantitatively synthesize in vitro and in vivo evidence on the antibacterial and therapeutic effects of equine regenerative medicine products, and to evaluate treatment efficacy against key pathogens via meta‑analysis.<b>Methods:</b> Following PRISMA guidelines, PubMed, Web of Science, and Scopus were searched for studies published from 2010 to 2025 that assessed at least one PRP‑ or MSC‑based intervention against bacterial pathogens in equine models. In vitro studies reporting colony‑forming unit (CFU) reductions were pooled using fixed‑effect meta‑analysis to calculate standardized mean differences (SMDs) with 95% confidence intervals (CIs). In vivo therapeutic outcomes were summarized narratively.<br><b>Results:</b> A total of 24 studies met inclusion criteria for the systematic review, of which 13 provided quantitative CFU data for meta‑analysis. Platelet‑derived products demonstrated a significant pooled SMD of 0.72 (95% CI: 0.24–1.20; <i>p</i> = 0.003) against <i>Staphylococcus aureus</i>, with low heterogeneity (I² = 27%). Against <i>Escherichia coli</i>, regenerative agents showed a marginal effect (SMD: 0.45; 95% CI: –0.07 to 0.98; <i>p</i> = 0.09; I² = 65%). MSC–based products yielded a non‑significant SMD of 0.34 (95% CI: –0.28 to 1.16; <i>p</i> = 0.23; I² = 38%) against <i>S. aureus</i>. Seven in vivo studies reported antimicrobial activity and clinical improvements in models of endometritis, wound infection, and arthritis. Combination therapies with antibiotics frequently exhibited synergistic biofilm disruption and enhanced bacterial clearance.<br><b>Conclusion:</b> Equine regenerative therapies are likely efficacious against Gram‑positive bacteria such as <i>S. aureus,</i> Gram-negative bacteria such as <i>E,coli</i> and hold promise for broader antimicrobial applications. Evidence for <i>PRP</i> and MSC‑based products is less robust and warrants further investigation including standardized product classification, rigorous randomized controlled trials, and consensus guidelines are needed to optimize clinical use of equine regenerative therapies and facilitate comparison across studies.