Meta-analysis of bacterial growth characteristics in platelet components: Refining the inputs of a simulation analysis comparing the relative safety of testing strategies

Background: The relative safety of bacterial risk control strategies for platelets that include culture with or without rapid testing has been compared using simulation analysis. A wide range of bacterial lag and doubling times were included. However, published data on growth rates are available and these data have not been synthesized. We conducted a systematic review and metaanalysis to estimate growth rates and used these estimates to refine a comparative safety analysis of bacterial risk control strategies in the FDA guidance Study Design and Methods: Data were extracted from published studies on bacterial growth rates in platelet components during storage. These data were used to estimate the practical range of growth rates. This refined the inputs for a simulation model comparing the safety of the testing strategies. Results: In total, 108 growth curves for 11 different aerobic organisms were obtained. Doubling times ranged from 0.8 to 12 h, but the lower 90% range was approximately 1-5 h. The revised comparative safety simulation using the narrower 1-5-h range showed similar rankings to the prior simulation, with 48-h large-volume delayed sampling with 7-day expiration (48C-7) demonstrating the lowest-ranking relative performance at the 103 and 105 colony forming unit (CFU)/mL exposure thresholds. Discussion: This was a two-step study. First, meta-analysis of published data on aerobic bacterial growth rates in stored platelets showed the vast majority of doubling times were 1-5 h. Next, an updated comparative safety simulation yielded similar results to a prior study, with 48C-7 showing the least favorable relative safety performance.