Abstract：
Identifying organisms directly from positive blood culture bottles using matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF MS) has many advantages to patients, clinical services, and laboratories. However, few published methods have demonstrated good performance using the current BioMérieux culture bottles and MALDI-TOF system: BacT/Alert FAN plus and Vitek MS. The effect of transporting bottles on test performance has not been assessed for any direct-from-bottle MS method. In this study, 802 positive blood culture bottles were analysed including 234 requiring inter-laboratory transport, using a method involving protein extraction with formic acid and acetonitrile. Correct identification rates were high for Staphylococcus aureus (58/58 of new diagnostic samples), Enterococcus faecalis (27/27), Gram-negative bacilli (160/176, 90.1%), and coagulase-negative Staphylococcus species (108/132, 81.8%). Three false identifications were made, none with clinical significance. For Gram-positive cocci in pairs or chains, more correct identifications were made from bottles analysed immediately compared to transported bottles (67% vs 44%, p=0.016), and longer transport time was associated with slightly lower probability of correct identification (OR 0.984 per additional hour, p=0.040). Transportation was not associated with a difference for other organism types. This technique is a vastly more cost-effective alternative to molecular techniques for rapid identification of bacteraemia isolates, and performance is minimally affected by inter-laboratory transport of bottles at ambient temperature.
摘要：
使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOFMS）直接从阳性血培养瓶中鉴定生物体对患者具有许多优势，临床服务,和实验室。然而,使用当前的BioMérieux培养瓶和MALDI-TOF系统，很少有公开的方法显示出良好的性能：BacT/AlertFANplus和VitekMS。对于任何直接来自瓶的MS方法,尚未评估运输瓶对测试性能的影响。在这项研究中,分析了802个阳性血培养瓶，其中234个需要实验室间运输，使用涉及用甲酸和乙腈提取蛋白质的方法。金黄色葡萄球菌的正确识别率很高（新诊断样本的58/58），粪肠球菌（27/27），革兰氏阴性杆菌（160/176，90.1%），凝固酶阴性葡萄球菌属（108/132，81.8%）。做了三个虚假的身份证明，无临床意义。对于成对或成链的革兰氏阳性球菌，与运输的瓶子相比，立即分析的瓶子获得了更正确的识别(67%对44%，p=0.016),较长的运输时间与正确识别的概率略低相关(每小时OR0.984，p=0.040)。运输与其他生物类型的差异无关。该技术是快速鉴定菌血症分离株的分子技术的更具成本效益的替代方法，和性能受实验室间运输的瓶子在环境温度下的影响最小。
