Sterilization of platelet concentrates at production scale by irradiation with short-wave ultraviolet light

Bacterial contamination of platelet concentrates (PCs) is recognized as a serious threat to transfusion safety. We developed a simple method for sterilization of PCs with short-wave ultraviolet light (UVC). The effects of treatment on the sterility of contaminated PCs and in vitro platelet (PLT) variables were evaluated.

Plasma-reduced PCs were prepared from pools of five buffy coats. Irradiation with UVC (wavelength, 254 nm) under vigorous agitation was from both sides of the irradiation bags. Kinetics of the inactivation of Bacillus cereus, Propionibacterium acnes, and Staphylococcus epidermidis were determined. PCs spiked with approximately 10 to 100 colony-forming units (CFUs)/mL of 10 bacteria species (n = 12/species) were irradiated with UVC doses between 0.25 and 0.4 J/cm(2) and tested for sterility by a commercially available bacterial detection system (BacT/ALERT, bioMérieux) after storage at 22 degrees C for 3 or 6 days. The influence of a dose of 0.3 J/cm(2) on PLT variables was investigated on Days 1, 4, and 6 after irradiation.

At 0.3 J/cm(2) all bacteria species tested were inactivated by more than 4 log. At this dose the influence of UVC on in vitro PLT variables was marginal; the storage stability for up to 6 days after treatment was maintained. PCs spiked with approximately 10 to 100 CFUs/mL were reproducibly sterilized in the dose range tested. In individual experiments with the spore former B. cereus, PCs were, however, unsterile after treatment.

Irradiation at UVC doses not detrimental to in vitro PLT variables sterilizes PCs contaminated with a wide range of different bacteria species.