Schmidt Michael, Hourfar Michael K, Nicol Sven-Boris, Wahl Alexandra, Heck Julia, Weis Christina, Tonn Torsten, Spengler Hans-Peter, Montag Thomas, Seifried Erhard, Roth W Kurt
Institute of Transfusion Medicine and Immunohematology, German Red Cross, Johann Wolfgang Goethe University, Frankfurt, Germany.
Transfusion. 2006 Aug;46(8):1367-73. doi: 10.1111/j.1537-2995.2006.00904.x.
Bacterial screening of all produced platelet concentrates (PCs) is implemented in many countries to reduce the risk of transfusion-transmitted sepsis. This study compares three rapid bacterial detection methods by imitating real-life conditions.
The sensitivity of a solid-phase scanning cytometer (optimized Scansystem, Hemosystem), fluorescence-activated cell sorting (FACS) analysis, and 16S RNA in-house nucleic acid testing (NAT) was evaluated by spiking PCs with four transfusion relevant bacteria (Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae, and Escherichia coli ). Two different inocula (10 colony-forming units [CFUs]/mL and 10 CFUs/bag) were used to simulate real-life conditions. Samples were taken at 12, 16, 20, and 24 hours after spiking.
With the high inoculum, NAT had a 100 percent rate of positive testing for all four types of bacteria (10/10 replicates) at each time point. With the exception of E. coli, the sensitivity of FACS and optimized Scansystem was comparable for the high inoculum. With the low inoculum, 60 percent of E. coli, 80 percent of B. cereus, 90 percent of K. pneumoniae, and 100 percent of S. aureus were NAT-positive 12 hours after spiking. In contrast, only 20 percent of E. coli, 10 percent of B. cereus, and 70 percent of K. pneumoniae were FACS-positive with the low inoculum 12 hours after spiking.
In summary, the preliminary data revealed a higher sensitivity for NAT in comparison to FACS and optimized Scansystem under the defined study conditions. To imitate real-life conditions, further spiking studies with a low inoculum (10 CFUs/bag) and slower growing organisms should be conducted to examine the sensitivity of available detection systems.
许多国家都对所有生产的血小板浓缩物（PCs）进行细菌筛查，以降低输血传播败血症的风险。本研究通过模拟实际情况比较三种快速细菌检测方法。
通过向PCs中加入四种与输血相关的细菌（金黄色葡萄球菌、蜡样芽孢杆菌、肺炎克雷伯菌和大肠杆菌），评估固相扫描细胞仪（优化后的Scansystem，Hemosystem）、荧光激活细胞分选（FACS）分析和16S RNA内部核酸检测（NAT）的灵敏度。使用两种不同的接种量（10个菌落形成单位[CFUs]/毫升和10个CFUs/袋）来模拟实际情况。加样后12、16、20和24小时采集样本。
对于高接种量，NAT在每个时间点对所有四种细菌的检测阳性率均为100%（10/10重复）。除大肠杆菌外，FACS和优化后的Scansystem对高接种量的灵敏度相当。对于低接种量，加样后12小时，60%的大肠杆菌、80%的蜡样芽孢杆菌、90%的肺炎克雷伯菌和100%的金黄色葡萄球菌NAT检测呈阳性。相比之下，加样后12小时，低接种量时只有20%的大肠杆菌、10%的蜡样芽孢杆菌和70%的肺炎克雷伯菌FACS检测呈阳性。
总之，初步数据显示，在规定的研究条件下，NAT比FACS和优化后的Scansystem具有更高的灵敏度。为模拟实际情况，应进行更多低接种量（10 CFUs/袋）和生长较慢微生物的加样研究，以检验现有检测系统的灵敏度。
