Impact of solvent/detergent treatment of plasma on transfusion-relevant bacteria

Background A solvent/detergent (S/D) treatment in a medical device has been developed for pathogen reduction of plasma for transfusion. Impact of S/D on bacterial growth and on the capacity of complement to kill bacteria has been investigated in this study. Study design and methods A pool of apheresis plasma from four donors was spiked with eight transfusion-relevant bacteria. Plasma was treated with 1% tri(n-butyl) phosphate and 1% Triton X-45 at 31°C for 90min and then extracted by oil at 31°C for 70min. Decomplemented plasma and Phosphate Buffer Saline were used as controls. Bacterial count was determined in samples taken immediately after spiking, or after S/D and oil treatment. Similar experiments were conducted using three individual recovered plasma donations. Bacteria growth inhibition tests were performed using discs soaked with plasma samples whether containing the S/D agents or not. Results The mean reduction factors of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae due to complement during S/D treatment were >8·75, 4·71, and 4·18 log in pooled plasma and >7·42, 2·24 and >6·08 log in individual plasmas, respectively. Bacillus cereus and Bacillus subtilis were inactivated by S/D (>7·04 and 1·60 log in pooled, and >6·06 and 2·39 in individual plasmas, respectively). Staphylococcus aureus, Staphylococcus epidermidis and Enterobacter cloacae did not multiply during S/D treatment of plasma. Growth inhibition tests revealed an inhibition of three Gram-negative bacteria by complement and all Gram-positive by S/D. Conclusion The S/D treatment of plasma does not alter the bactericidal activity of complement, and inactivates some Gram-positive bacteria.