Clinical significance of bacteriologic screening in platelet concentrates.

BACKGROUND: Despite routine bacterial screening with a bacterial culturing system (BacT/ALERT, bioMerieux) of platelet (PLT) concentrates, two cases of life-threatening sepsis attributed to transfused PLT products contaminated with Bacillus cereus were reported to the regional hemovigilance office in the southwest region of the Netherlands. These reports necessitated a retrospective evaluation of the currently applied bacteriologic screening program. STUDY DESIGN AND METHODS: Bacteriologic screening of all PLT concentrates on production was introduced in October 2001. Aliquots (5-10 mL) of pooled PLT concentrates in additive solution were taken for cultures with the BacT/ALERT system 14 to 24 hours after donation. The total culturing period was 7 days and in case of positive signals, identification cultures were taken from the culture bottles. The results of the bacterial screening, identification, and clinical significance of possibly contaminated pooled PLT concentrates were evaluated retrospectively over a 2-year period. RESULTS: In this period, a total of 28,104 pooled PLT concentrates were produced. Positive bacterial screening was found in 0.72 percent (n = 203). Of these, in 184 pooled PLT concentrates bacteria were cultured and identified, and in the remaining 19 (9.4%) identification cultures were negative. Before a positive screening was found, 113 PLT concentrates had already been transfused without the occurrence of clinical significant transfusion reactions. CONCLUSION: Bacterial contamination of pooled PLT concentrates was not related to clinically significant transfusion reactions. Despite negative screening for bacterial contamination, life-threatening transfusion-transmitted infections by contaminated PLT products can still occur. Other strategies should be applied to guarantee a higher degree of bacteriologic safety.

Evaluation of a new citrate-acetate-NaCl platelet additive solution for the storage of white cell-reduced platelet concentrates obtained from half-strength CPD pooled buffy coats.

BACKGROUND: A new citrate-acetate-NaCl platelet additive solution, identified as PAS 2, was developed to prepare platelet concentrates (PCs) from pooled 0.5 CPD buffy coats (BCs). STUDY DESIGN AND METHODS: A study was undertaken to evaluate PAS 2 in vitro (n = 8) and in vivo (n = 9) against a commercially available solution (Plasma-Lyte A). In a paired in vitro study, a comparison was made of platelet and white cell concentration; blood gases and bicarbonate; glucose and lactate concentration; total intracellular concentration of adenine nucleotides and beta-thromboglobulin release. RESULTS: A lower platelet yield (p < 0.0001) and a higher beta-thromboglobulin release (p < 0.01) are observed with Plasma-Lyte A. For this reason, half-strength (0.5) CPD was changed to full-strength CPD in the clinical study with Plasma-Lyte A. In a clinical evaluation of nine patients with bone marrow failure, all received PCs with both PAS 2 and Plasma-Lyte A that had a shelf life of at least 4 days. Corrected count increments (CCls) were as follows, on average (95% Cl): the CCl at 1 to 4 hours was 22.4 (95% Cl, 15.2-29.4) for PAS 2 and 24.0 (95% Cl, 16.9-31.2) for Plasma-Lyte A; that at 12 to 24 hours was 11.3 (95% Cl, 4.1-18.4) for PAS 2 and 14.2 (95% Cl, 7.1-21.3) for Plasma-Lyte A; and that at 36 to 48 hours was 4.2 (95% Cl, -3.0-11.3) for PAS 2 and 8.7 (95% Cl, 1.1-16.2) for Plasma-Lyte A. No significant difference between the two solutions was found. CONCLUSIONS: PAS 2 and Plasma-Lyte A make important contributions to platelet transfusion quality improvement and give an excellent CCl even after 4 days of storage.