Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 1 2026 02 14 74 81 Akbar Hashemi Tayer Noncommunicable Diseases Research Center, Jahrom University of Medical Sciences, Jahrom, Iran Gholamreza Shokoohi Department of Parasitology and Mycology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran 2024 05 15 2026 02 07 Background and Objectives: Umbilical cord blood-derived platelet gel (CBPG) is rich in growth factors (GFs) and antimicrobial peptides. This study evaluated its in vitro antibacterial and antifungal activity against dominant nosocomial pathogens. Materials and Methods: In this experimental study, CB samples were taken from 12 healthy pregnant women post-cesarean at Motahari Hospital, Jahrom. Platelet -rich plasma (PRP) was isolated using a two-step centrifugation protocol (soft-spin: 200×g, 10 min; hard spin:1000×g, 15 min, 22°C) and activated with calcium and human thrombin to form PG. Antimicrobial effect of PG was determined against Klebsiella pneumoniae, Methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, Pseudomonas aeruginosa, Candida albicans, Aspergillus spp., and Penicillium spp. using broth microdilution and time-kill assays per CLSI guidelines. Results: PG exhibited strong bacteriostatic activity against MRSA and K. pneumoniae (MIC 2.2–2.8 × 10⁸ platelets/mL; 1.7-1.8 log₁₀ reduction at 24 h, p < 0.001), while PRP was moderately active and PPP was ineffective. No significant activity was observed against P. aeruginosa or A. baumannii (p= 0.2). PG showed sustained fungistatic effects (MIC: 1.9-4.2× 10⁸ platelets/mL up to 72 h). Conclusion: CBPG exhibits potent bacteriostatic and fungistatic effects, particularly against MDR Gram-positive bacteria, offering a novel autologous antimicrobial. https://ijm.tums.ac.ir/index.php/ijm/article/view/4789 https://ijm.tums.ac.ir/index.php/ijm/article/download/4789/1864