Assessment of bacterial growth in leukoreduced cold‐stored whole blood supports overnight hold at room temperature prior to filtration: A pilot study

Abstract

Background and Objectives Whole blood (WB) transfusion has regained attention to treat trauma patients. We reported no significant changes in in vitro quality through 21 days of cold storage for leukoreduced WB (LCWB) when time to filtration was extended from 8 to 24 h from collection. This study evaluated the impact of extended WB‐hold at room temperature (RT) prior to leukoreduction on proliferation of transfusion‐relevant bacteria. Materials and Methods WB units were spiked with suspensions of Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Listeria monocytogenes prepared in saline solution (SS) or trypticase soy broth (TSB) to a concentration of ~0.2 CFU/ml (N = 6). Spiked units were held at RT for 18–24 h before leukoreduction and cold‐stored for 21 days. Bacterial growth was determined on days 2, 7, 14 and 21. In vitro quality of WB inoculated with unspiked diluents was assessed. Results K. pneumoniae and S. pyogenes proliferated in WB prior to leukoreduction reaching concentrations ≤102 CFU/ml. These bacteria, however, did not proliferate during the subsequent cold storage. S. aureus did not survive in WB while L. monocytogenes reached a concentration of ~102 CFU/ml by day 21. LCWB in vitro quality was not affected by SS or TSB. Conclusion Extended WB‐hold prior to leukoreduction allowed proliferation of bacteria able to resist immune clearance, although they did not grow to clinically significant levels. While L. monocytogenes proliferated in LCWB, clinically relevant concentrations were not reached by day 21. These data suggest that transfusing LCWB may not pose a significant bacterial contamination safety risk to transfusion patients.

Growth and Distribution of Bacteria in Contaminated Whole Blood and Derived Blood Components

“…Spiking experiments are needed to generate data on bacterial contamination of blood products. Most previous studies of bacterial growth in WB units are limited to single bacterial strains [4][5][6] or high spiking concentrations of 10 2 CFU/mL or higher [7][8][9][10], neither of which reflects the true strain diversity and low initial numbers of bacteria present at the time of blood donation.…”