Ramirez-Arcos Sandra, DiFranco Caesar, McIntyre Terri, Goldman Mindy
Canadian Blood Services, Ottawa, Ontario, Canada.
Transfusion. 2017 Sep;57(9):2174-2181. doi: 10.1111/trf.14202. Epub 2017 Jun 26.
Canadian Blood Services screens 100% of platelet concentrates (PCs) for bacterial contamination with the BacT/ALERT system. Quality-control sterility testing of 1% (≥10 units) of outdated PCs is performed monthly. Data from routine screening, quality-control testing, and septic reactions obtained from 2010 to 2016 are presented herein.
In total, 601,988 buffy coat PC pools and 186,737 apheresis PCs were routinely screened with aerobic cultures over 6 years. Outdate quality-control testing of 8535 buffy coat and 8498 apheresis PCs was performed using aerobic and anaerobic cultures during the same period. Results were classified as "true-positives" when the same bacterium was isolated in initial and confirmatory cultures or "false-negatives" when bacteria were missed in early screening and were captured during quality-control sterility testing or through investigation of sepsis cases.
During routine screening, the true-positive rates between buffy coat (0.94 per 10,000) and apheresis (0.96 per 10,000) PCs were similar (p = 0.9473). Seventy-five bacteria isolated during PC screening included Gram-positive and Gram-negative organisms. Six false-negative septic reactions were reported that implicated coagulase-negative staphylococci (n = 3) and Staphylococcus aureus (n = 3) for approximate rates of 1 per 100,000 transfusion reactions and 1 per 500,000 fatalities. During quality-control testing, the false-negative rates between buffy coat (8 per 10,000) and apheresis (9 per 10,000) PCs were similar (p = 0.7897). All 15 quality-control isolates were Gram-positive bacteria.
The current bacterial screening protocol is efficacious for identifying Gram-negative bacteria. However, the high proportion of Gram-positive organisms detected on outdate quality-control testing and septic transfusion events demonstrates a residual safety risk that merits further intervention.
加拿大血液服务中心使用BacT/ALERT系统对100%的血小板浓缩物（PCs）进行细菌污染筛查。每月对1%（≥10单位）过期的PCs进行质量控制无菌检测。本文展示了2010年至2016年从常规筛查、质量控制检测和败血症反应中获得的数据。
在6年时间里，总共对601,988个 Buffy 层PC混合样本和186,737个单采PCs进行了需氧培养的常规筛查。同期，使用需氧和厌氧培养对8535个Buffy层PCs和8498个单采PCs进行了过期质量控制检测。当在初始培养和确认培养中分离出相同细菌时，结果分类为“真阳性”；当早期筛查中遗漏细菌并在质量控制无菌检测或通过败血症病例调查发现时，结果分类为“假阴性”。
在常规筛查期间，Buffy层PCs（每10,000个中有0.94个）和单采PCs（每10,000个中有0.96个）的真阳性率相似（p = 0.9473）。PC筛查期间分离出的75种细菌包括革兰氏阳性菌和革兰氏阴性菌。报告了6例假阴性败血症反应，涉及凝固酶阴性葡萄球菌（n = 3）和金黄色葡萄球菌（n = 3），输血反应发生率约为每100,000次1例，死亡率约为每500,000例1例。在质量控制检测期间，Buffy层PCs（每10,000个中有8个）和单采PCs（每10,000个中有9个）的假阴性率相似（p = 0.7897）。所有15个质量控制分离株均为革兰氏阳性菌。
当前的细菌筛查方案对于识别革兰氏阴性菌是有效的。然而，在过期质量控制检测和败血症输血事件中检测到的革兰氏阳性菌比例较高，表明存在残留安全风险，值得进一步干预。
