Photochemical inactivation of pathogenic bacteria in human platelet concentrates

nated with low levels of bacteria that can cause septicemia and death in patients receiving transfusion therapy. We eval-uated the efficacy of a photochemical decontamination (PCD) technique using 8-methoxypsoralen (8-MOP) and long wavelength UV light (UVA) to inactivate bacteria in standard therapeutic PC. Twelve phylogenetically distinct pathogenic bacteria, 5 gram-positive and 7 gram-negative organisms, were seeded into PC to a final challenge dose ranging from IO5 t o lo7 colony-forming units (CFU)/mL. Contaminated PC were treated with 8-MOP (5 pg/mL) and 5 J/cm2 of UVA, a PCD treatment regimen found to adequately preserve in vitro platelet function. Greater than IO6 CFUlmL of all 5 gram-positive (Staphylococcus aureus, Streptococcus epid-ermidis, Streptococcus pyogenes, Listeria monocytogenes, and Corynebacterium minutissimum) and 2 of the gram-neg