Abstract：
Salmonella is a major cause of foodborne diseases worldwide. Conventional rapid assays for detecting Salmonella in real samples often encounter severe matrix interference or detect a limited number of species of a genus, resulting in inaccurate detection. In this study, we developed a method that combined phage-based magnetic capture with real-time recombinase polymerase amplification (RPA) for the rapid, highly sensitive, and specific detection of Salmonella in milk with an ultra-low detection limit. The Felix O-1 phage-conjugated magnetic beads (O-1 pMBs) synthesized in this method showed excellent capture ability for Salmonella spp. and ideal specificity for non-Salmonella strains. After O-1 pMBs-based magnetic separation, the limit of detection of the real-time RPA assay was 50 cfu/mL in milk samples, which was significantly increased by a magnitude of 3 to 4 orders. The method exhibited a high sensitivity (compatibility) of 100% (14/14) for all tested Salmonella serotype strains and an ideal specificity (exclusivity) of 100% (7/7) for the tested non-Salmonella strains. The entire detection process, including Salmonella capture, DNA extraction, and real-time RPA detection, was completed within 1.5 h. Furthermore, milk samples spiked with 10 cfu/25 mL of Salmonella were detected positive after being cultured in buffered peptone water for only 3 h. Therefore, the proposed method could be an alternative for the rapid and accurate detection of Salmonella.
摘要：
沙门氏菌是世界范围内食源性疾病的主要病因。用于检测真实样品中沙门氏菌的常规快速测定法通常会遇到严重的基质干扰或检测到有限数量的属物种。导致检测不准确。在这项研究中,我们开发了一种将基于噬菌体的磁性捕获与实时重组酶聚合酶扩增（RPA）相结合的方法，高度敏感,牛奶中沙门氏菌的特异性检测具有超低的检测限。用这种方法合成的FelixO-1噬菌体偶联磁珠（O-1pMBs）对沙门氏菌具有出色的捕获能力。和理想的非沙门氏菌菌株的特异性。在基于O-1pMBs的磁分离之后，实时RPA测定的检测限（LOD）为牛奶样品中的50cfu/mL，显着增加了3-4个数量级。该方法对所有测试的沙门氏菌血清型菌株表现出100%(14/14)的高灵敏度(相容性)和对测试的非沙门氏菌菌株表现出100%(7/7)的理想特异性(排他性)。包括沙门氏菌捕获在内的整个检测过程,DNA提取,实时RPA检测在1.5h内完成。此外，添加了10cfu/25mL沙门氏菌的牛奶样品在缓冲蛋白胨水中培养仅3小时后检测到阳性。因此，该方法可作为沙门氏菌快速、准确检测的替代方法。
