Wagner S J, Robinette D
Product Development Department, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross Biomedical Services, Rockville, Maryland, USA.
Transfusion. 1996 Nov-Dec;36(11-12):989-93. doi: 10.1046/j.1537-2995.1996.36111297091744.x.
Although infrequent, episodes of transfusion-associated bacterial sepsis may lead to serious outcomes or death and therefore are of concern. This study evaluates the sensitivity of three surrogate tests for the presence of bacteria in platelet concentrates: cessation of swirling, low extracellular pH, and low plasma glucose levels.
Day 0 platelet concentrates were inoculated with low levels of one of seven bacterial strains and stored with agitation at 20 to 24 degrees C for up to 5 days. In the morning and afternoon of each day of storage, bacterial levels were ascertained by quantitative plate culture, and platelet concentrates were tested for platelet pH, plasma glucose, and swirling. Quantitative and semiquantitative dipstick techniques were used to determine pH and glucose levels.
Platelet concentrates had attained stationary phase growth of Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Enterobacter cloacae, Streptococcus mitis, or Staphylococcus epidermidis (> or = 10(7) -10(8) colony-forming units [CFU]/mL) before either the swirling or dipstick methods suggested the presence of bacteria. The sensitivity of swirling and glucose tests for detecting bacterial contamination in platelet concentrates was generally comparable. Although the sensitivity of the pH test was generally similar to that of swirling and glucose tests for most bacteria, platelet concentrates contaminated with E. cloacae had normal pH despite the presence of high levels of bacteria (> or = 10(7)-10(8) CFU/mL).
The sensitivity in detection of bacteria in platelet concentrates by the swirling technique or by measuring extracellular pH or plasma glucose is less than the sensitivity reported for microscopy with Gram stain (10(5)-10(6) CFU/mL), fluorescence microscopy with acridine orange stain (10(4)-10(5) CFU/mL), chemiluminescence detection of ribosomal RNA (10(3)-10(4) CFU/mL), and automated bacterial culture (1 CFU/sample volume).
尽管输血相关细菌性败血症的发作并不常见，但可能导致严重后果甚至死亡，因此备受关注。本研究评估了三种替代检测方法对血小板浓缩物中细菌存在情况的敏感性：漩涡停止、细胞外pH值降低和血浆葡萄糖水平降低。
第0天的血小板浓缩物接种低水平的七种细菌菌株之一，并在20至24摄氏度下搅拌储存长达5天。在储存的每一天的上午和下午，通过定量平板培养确定细菌水平，并对血小板浓缩物进行血小板pH值、血浆葡萄糖和漩涡检测。使用定量和半定量试纸技术测定pH值和葡萄糖水平。
在漩涡法或试纸法提示存在细菌之前，血小板浓缩物已达到化脓性链球菌、金黄色葡萄球菌、大肠杆菌、蜡样芽孢杆菌、阴沟肠杆菌、缓症链球菌或表皮葡萄球菌的稳定期生长（≥10⁷ - 10⁸菌落形成单位[CFU]/mL）。漩涡法和葡萄糖检测法检测血小板浓缩物中细菌污染的敏感性通常相当。尽管pH检测法对大多数细菌的敏感性通常与漩涡法和葡萄糖检测法相似，但被阴沟肠杆菌污染的血小板浓缩物尽管存在高水平细菌（≥10⁷ - 10⁸ CFU/mL），其pH值仍正常。
通过漩涡技术或测量细胞外pH值或血浆葡萄糖来检测血小板浓缩物中细菌的敏感性低于革兰氏染色显微镜检查（10⁵ - 10⁶ CFU/mL）、吖啶橙染色荧光显微镜检查（10⁴ - 10⁵ CFU/mL）、核糖体RNA化学发光检测（10³ - 10⁴ CFU/mL）和自动化细菌培养（1 CFU/样品体积）所报告的敏感性。
