A more effective treatment of bacteremia requires a diagnostic platform that is both sensitive, accurate and rapid. Currently, clinical laboratory techniques require growth of bacteria prior to diagnosis, take days to complete, and leave empiric therapy and broad spectrum antibiotics as the only option at the onset of treatment. In order to bypass this growth requirement, we engineered a system that purifies bacteria from blood to improve performance in a bacteriophage-based luminescence assay. To perform the purification, we used acoustophoresis in plastic microfluidic chips, enabling future development into a low cost point-of-care system. Acoustophoresis achieves differential separation on the basis of size differences between bacteria and blood cells. We show isolation of three known pathogen species, including members of both Gram-negative and positive-bacteria from blood, and show isolation at clinically relevant concentrations. Using the device as a preparation step prior to the bacteriophage-based luminescence assay, we demonstrate a 33-fold improvement in limit of detection, compared with the unpurified sample, achieving a limit of detection of 6 bacteria.

中文翻译：

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塑料微流体中的声学分离，可使用工程化噬菌体快速检测血液中的细菌†

要更有效地治疗菌血症，需要一个既灵敏，准确又快速的诊断平台。目前，临床实验室技术要求细菌在诊断之前先生长，需要几天才能完成，并且留下经验疗法和广谱抗生素作为治疗开始的唯一选择。为了绕过这种增长需求，我们设计了一种系统，该系统可从血液中纯化细菌，从而提高基于噬菌体的发光测定的性能。为了进行纯化，我们在塑料微流控芯片中使用了电泳技术，从而可以将来开发成低成本的即时护理系统。声学电泳根据细菌和血细胞之间的大小差异实现差异分离。我们展示了三种已知病原体的分离，包括血液中革兰氏阴性和阳性细菌的成员，并在临床相关浓度下显示出隔离。使用该设备作为基于噬菌体的发光测定之前的准备步骤，与未纯化的样品相比，我们证明了检出限提高了33倍，实现了6种细菌的检出限。