Search

Background and Objectives: Platelet concentrates (PC) are stored at 20-24°C to maintain platelet functionality, which may promote growth of contaminant bacteria. Alternatively, cold storage of PC limits bacterial growth; however, data related to proliferation of psychotrophic species in cold-stored PC (CSP) are scarce, which is addressed in this study., Materials and Methods: Eight laboratories participated in this study with a pool/split approach. Two split PC units were spiked with ~25 colony forming units (CFU)/PC of Staphylococcus aureus, Klebsiella pneumoniae, Serratia liquefaciens, Pseudomonas fluorescens and Listeria monocytogenes. One unit was stored under agitation at 20-24°C/7 days while the second was stored at 1-6°C/no agitation for 21 days. PC were sampled periodically to determine bacterial loads. Five laboratories repeated the study with PC inoculated with lyophilized inocula (~30 CFU/mL) of S. aureus and K. pneumoniae., Results: All species proliferated in PC stored at 20-24°C, reaching concentrations of ≤10 9  CFU/mL by day 7. Psychrotrophic P. fluorescens and S. liquefaciens proliferated in CSP to ~10 6  CFU/mL and ~10 5  CFU/mL on days 10 and 17 of storage, respectively, followed by L. monocytogenes, which reached ~10 2  CFU/mL on day 21. S. aureus and K. pneumoniae did not grow in CSP., Conclusion: Psychrotrophic bacteria, which are relatively rare contaminants in PC, proliferated in CSP, with P. fluorescens reaching clinically significant levels (≥10 5  CFU/mL) before day 14 of storage. Cold storage reduces bacterial risk of PC to levels comparable with RBC units. Safety of CSP could be further improved by implementing bacterial detection systems or pathogen reduction technologies if storage is beyond 10 days., (© 2024 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd on behalf of International Society of Blood Transfusion.)

Background and Objectives: Platelet concentrates (PCs) contaminated with Cutibacterium acnes are often transfused prior to detection by the BACT/ALERT system. Though C. acnes is implicated in mild transfusion reactions, delayed clinical effects are unknown. This study assessed the ability to enhance C. acnes detection by supplementing culture media with Tween 80 (T80, an oleic acid source) and a commercial nutrient supplement., Materials and Methods: Anaerobic culture bottles (BPN) were supplemented with T80 or oleic acid. T80-supplemented BPN bottles were inoculated with four C. acnes isolates (10 or 100 colony-forming units [CFU]/bottle) or other transfusion-relevant bacteria (10 CFU/bottle). Samples of plasma containing SSP+ (platelet additive solution [PAS]) (PAS-plasma) at different concentrations, plasma-PCs and PAS-PCs, spiked with two C. acnes isolates (10 CFU/bottle), were inoculated into T80-supplemented BPN bottles. Furthermore, plasma-PCs were spiked with C. acnes and tested in BPN bottles supplemented with the BD Difco Supplement VX (BDVx). Bottles were incubated in the BACT/ALERT system and times to detection (TtoD) were compared (N = 3)., Results: A reduction in TtoD of ≤3.5 days was observed for C. acnes in T80-supplemented BPN, while other species did not show the same effect. However, false positives were observed when T80-supplemented BPN was inoculated with PAS-plasma (except for 70% PAS:30% plasma), plasma-PCs or PAS-PCs. Oleic acid supplementation also resulted in false positives. Interestingly, BDVx-supplemented BPN reduced the TtoD of C. acnes in PCs by ≤1.2 days (p < 0.05), with no false-positive results., Conclusion: BDVx supplementation for detection of C. acnes from PCs could result in timely unit retrieval, preventing the transfusion of contaminated products. In clinical settings, T80 supplementation could significantly enhance C. acnes detection from non-blood-derived samples., (© 2023 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd on behalf of International Society of Blood Transfusion.)

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 ≤10 2 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 ~10 2 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., (© 2022 International Society of Blood Transfusion.)