BacT／ALERT 3D血液样本细菌检测中假阳性反应的分析

本研究通过分析BacT／ALERT 3D系统血液样本细菌检测中的假阳性反应结果，评估该系统的特异性，以减少假阳性反应的产生。对5年间BacT／ALERT 3D所有阳性反应瓶进行细菌分离和鉴定，并对留样和可获得的相关血袋进行重复试验，共检测11395份血液样本。结果表明：初次培养阳性反应122份（1．07％），其中107份（88．7％）从阳性反应的培养瓶中分离出细菌，另15份（12．3％）中未分离出任何细菌。细菌生长引起的阳性反应的监测曲线显示明显的急剧上升。结论：在检测过程中维持孵箱温度的稳定、避免孵育箱的温度急剧降低可减少假阳性信号的产生；对报告阳性的培养瓶进行进一步的孵育，观察生长曲线是否有急剧上升的对数生长期有助于鉴别假阳性反应，从而提高BacT／ALERT 3D系统的特异性。     

全自动快速微生物培养检测系统在结核病诊治中的运用

传统的细菌学检测方法简单、经济，易于推广使用。但是存在阳性检出率低，耗时长，难以标准化等缺点，更耽误了病人的诊疗时间。因此缩短检测的时间，提高分枝杆菌的阳性检出率是一个迫切的问题。我院于2003年引进荷兰欧嘉隆公司生产的全自动微生物快速培养检测系统（简称BacT／ALERT3D）。为了解该系统的临床运用价值，我们用BacT／ALERT3D仪快速培养检测432份临床患者标本并与罗氏法进行比较。现报告如下。     

一种新的实时荧光定量PCR方法对血小板制品细菌污染检测效果的评价

目的建立一种自主研发的针对细菌16 S r DNA基因的实时荧光定量PCR(Real-time PCR)方法并评价该方法对浓缩血小板制品中细菌污染检测的效果。方法设计16S r DNA基因保守区引物,构建SYBR Green Real-time PCR反应体系;然后分别将大肠杆菌、金黄色葡萄球菌、表皮葡萄球菌、蜡样芽孢杆菌和绿脓杆菌以初始浓度为1CFU/m L、10 CFU/m L和100 CFU/m L接种到浓缩血小板中,经22℃保存7 d后,用实时定量荧光PCR方法进行细菌检测。结果细菌污染后的血小板在常规保存条件下,最长保存期7 d,不同接种浓度的细菌生长情况的变化趋势基本一致,所有种类的细菌均在d 1、2表现出迅猛的增殖高峰,d 3以后增殖趋于平缓。结论该Real-time PCR检测体系可定量地检测出血小板的细菌污染的情况,可适用于血小板输注前的快速细菌污染检测。     

Differences in time to detection and recovery of Mycobacterium spp. between the MGIT 960 and the BacT/ALERT MB Automated Culture Systems

Mycobacterium sp. recovery and time to detection were compared in the MGIT 960 and BacT/ALERT MB automated broth culture systems. The MGIT 960 demonstrated shorter time to detection (13.5 versus 25.2 days) and greater sensitivity (100% versus 66.6%) for recovery of the Mycobacterium tuberculosis complex than the BacT/ALERT MB system.     

Fatal reaction to transfusion of red-cell concentrate contaminated with Serratia liquefaciens

A 60-year-old woman undergoing surgery died from endotoxic shock and DIC after receiving a 19-day-old unit of optimal additive red-cell concentrate found contaminated with Serratia liquefaciens . No source of contamination could be found. This normally free-living organism is usually of low pathogenicity. It is a very unusual contaminant of stored donated blood, although it appears to be on the increase. When transfused, blood contaminated with S. liquefaciens always causes severe morbidity and is associated with a high death rate. This is the fifth report in the English literature.     

Bacterial contamination of single-donor blood components

SUMMARY. An analysis was performed of the microbiological laboratory quality control data for the past 9 years (1985–1993). Bacterial contamination was detected in 100 of 25,171 tested blood components. Single-donor platelet concentrates had a contamination incidence of 25 in 5889 (0.42%); whole blood samples were contaminated at a rate of 1 in 2973 (0.03%) and red cell concentrates at a rate of 73 in 15, 317 (0.48%); of 992 samples of fresh frozen plasma only 1 was contaminated (0.1%). Gram-positive staphylococci comprised 75% of cases and Gram-negative rods 10%. This frequency of laboratory-detected bacterial contamination contrasts with the low rate of transfusion-associated septicaemic events.     

Fatal Clostridium perfringens sepsis from a pooled platelet transfusion

A male patient with acute myeloid leukaemia received a pooled platelet preparation prepared by Opti-press^TM system on the last day of its shelf life. The patient collapsed after two-thirds of the contents had been transfused. Clostridium perfringens was isolated from the platelet bag within 18 h of the acute event. Metronidazole, gentamicin and Clostridium antiserum were then administered in addition to the broad spectrum antibiotics started previously. However, the patient died 4 days after the platelets were transfused. The cause of death was given as cardiovascular shock, entirely compatible with an overwhelming bacteraemic and septic episode. A coroner's verdict of accidental death due to transfusion of a contaminated unit of platelets was recorded.
On subsequent investigation Cl. perfringens type A serotype PS68,PS80 (identical to that found in the platelet bag) was cultured from the venepuncture site of the arm of one of the donors who contributed towards the platelet pool. The donor had two young children and frequently changed nappies. Faecal contamination of the venepuncture site was the suspected source for the transmission of Cl. perfringens, an organism commonly found in the soil and intestinal tract of humans. This case dramatically highlights the consequences of transfusing a bacterially contaminated unit. It is vital that such incidents are investigated and reported so that the extent of transfusion-associated bacterial transmission can be monitored and preventative measures taken if possible.     

细菌筛检在预防和控制血小板细菌污染方面的有效性

本研究探讨用血小板细菌筛检及24小时锁定的方法预防和控制血小板细菌污染的有效性。用BacT/A-LERT细菌培养仪对保存24小时后（22℃振荡保存）的单采血小板（机器采集的血小板）进行细菌筛检。在无菌条件下抽取5袋样品,并合并成1袋后分别接种于需氧培养液和厌氧培养液中,同时将被抽检的血小板进行锁定。接种后的培养液置培养箱中培养24小时后,如结果为阴性,则该血小板可放行。如出现阳性,对阳性结果进行菌种鉴定,并取留样样品进行复试。结果表明：8017袋单采血小板中,初筛为阳性的16袋（0.2%）,复筛确认阳性的4袋（0.05%）;进一步菌种分析显示3袋为金黄色葡萄球菌,1袋为耳状葡萄球菌。结论：血小板细菌筛检、24小时锁定作为血小板常规检测项目是非常必要的,它对于预防和控制血小板细菌污染是有效而且适宜的。     

基于微流控芯片的实时荧光定量 ＰＣＲ 技术快速检测血小板制剂细菌 污染

摘要：目的 通过微流控芯片检测平台应用 Ｔａｑｍａｎ 探针的实时定量 ＰＣＲ 技术对血小板制剂中的细菌１６Ｓ ｒＤＮＡ 进行检测,探 讨该体系在血小板细菌污染的快速检测的应用。方法 向机采血小板中人为添加一定浓度的金黄色葡萄球菌或铜绿假单胞 菌,模拟成１０２ ～１０８ ＣＦＵ／ ｍＬ 细菌污染的血液标本,经１０倍梯度稀释后进行细菌计数及微流控芯片 ＦＱ ＰＣＲ 检测细菌１６Ｓ ｒＤＮＡ,并 对检测体系进行特异性、检出限和重复性评价。结果 微流控芯片 ＦＱ ＰＣＲ 体系特异性较强,探针和引物对阳性标本均有反 应,与空白对照无反应。对污染血小板的金黄色葡萄球菌,该方法的最低检出限为 ８６５ ＣＦＵ／ ｍＬ,而对铜绿假单胞菌的最低检 出限为 ８８５ ＣＦＵ／ ｍＬ。当金黄色葡萄球菌与铜绿假单胞菌浓度分别达到最低检测限时,空白对照与各细菌组的 Ｃｔ 值之差分别 为 ４．３５±１．０１ 和 ２．０３±０．６１。各浓度菌液提取的 ＤＮＡ 进行微流控芯片 ＦＱ ＰＣＲ 扩增后的 Ｃｔ 值计算重复性指数在 ０．０１２～ ０．０５２ 范围内。结论 微流控芯片 ＦＱ ＰＣＲ 检测平台可特异、有效地检出血小板中的细菌污染,为确保输血安全提供帮助。