(P-BC-33) Evaluation Of Pathogen Reduction Efficacy In Platelet Concentrates Until End Of Shelf-Life With Two Different Automated Bacterial Detection Systems 

The storage condition of platelet components (PCs) (20-24°C under continuous agitation) bears an increased risk for bacterial growth to clinically relevant levels in case of contamination. The incidence of septic transfusion reactions (STRs) is globally often underreported in routine treatment. Active hemovigilance studies revealed an STR incidence of approx.1:10.000 (Hong H et al., 2016. Blood 127: 496-502), despite interventions to increase safety. Pathogen reduction (PR) was shown to inactivate bacteria effectively. However, most experiments were conducted assessing bacterial growth pre-and post-treatment. The aim of our study was the assessment of bacterial safety with transfusion-relevant species, post PR-treatment, until end of shelf-life (5 days) and the maximum shelf life according to product specifications (7-days) using two different bacterial detection technologies, minimizing the risk of false-negative results.

Study

Design/Methods: Single-donor platelet concentrates (PCs) in 100% plasma were prepared from individual 450 mL whole blood donations within 8 h post collection by the PRP method. Five ABO-identical single-donor PCs were pooled to obtain an adult transfusion dose (ATD), containing ≥3x10¹¹ platelets. ATDs were inoculated with a bacterial load of 5x10⁴/mL with different bacterial species (identity confirmed by biochemical analysis with a Phoenix device (Becton-Dickinson)), respectively. ATDs were incubated for 3 h at 20-24°C under continuous agitation followed by PR-treatment with amotosalen/UVA (AS) (INTERCEPT Blood System, Cerus Corporation). ATDs were further incubated until day 7. Samples (15 mL) were taken from each unit pre-inoculation, pre-treatment, post-treatment, at day 5, and day 7, under sterile conditions using a satellite bag. Samples were analyzed for bacterial growth with two automated bacterial detection systems, BacT/Alert (Biomerieux, 10 mL, 5 days incubation until negativity) and eBDS (Haemonetics, 5 mL).

Results/Findings: The average pre-treatment volume of ATDs (n=8) was 289.1 ± 33.4 mL, the average post-treatment volume 272.2 ± 34 mL (5.8% processing loss). The average pre-treatment platelet count was 3.5x10¹¹ ± 0.5, the post-treatment platelet count was 3.1x10¹¹ ± 0.4 (11.4% processing loss). Four ATDs were inoculated with S. aureus, 2 with E. coli and 2 with P. aeruginosa. All units were negative pre-inoculation using both bacterial detection systems, positive pre-PR-treatment, and negative directly post PR-treatment as well as at day 5 and 7 of storage.

Conclusions:

AS-treatment reliably inactivated clinical relevant bacterial loads of 3 species with effectively until end of shelf-life (terminal sterility) at day 5 and maximum shelf life according to product specifications at day 7.