A laboratory comparison of pathogen reduction technology treatment and culture of platelet products for addressing bacterial contamination concerns

Concerns over the risk of bacterial contamination of platelet products have led to implementation of bacteria culture and other screening methods. New approaches for dealing with this issue have also been proposed. A direct comparison of treatment with riboflavin and ultraviolet (UV) light (Mirasol pathogen reduction technology [PRT] system) versus bacterial culture testing (two-bottle system, 48-hour quarantine) was undertaken to compare their effectiveness. Thirteen clinically relevant bacterial organisms (20 strains) were used in this evaluation. Results were compared with spiking levels at 20 to 100 colony-forming units (CFUs) per product and at less than 20 CFUs per product. At spiking levels of 20 to 100 CFUs per product, the riboflavin and UV light process demonstrated 91% effectiveness against a broad spectrum of bacteria. In comparison, the culture method demonstrated an ability to detect up to 91% of the same contaminants, when used in the two-bottle, 48-hour-to-release configuration. At lower initial titers of contaminating agents (< 20 CFUs per product), the effectiveness of PRT increased to 98% whereas the culture method effectiveness decreased to 66%. Effectiveness of the culture method further decreased to 60% when a one-bottle system was used. The results from this work suggest that the riboflavin and UV light process may provide up to 98% protection against transfusion of bacterially contaminated units at the most clinically relevant contamination levels (< 20 CFUs per product). This compares favorably to the 60% to 66% effectiveness of bacterial culture testing using a 48-hour quarantine period before product release.