Suh Soo Hwan, Choi Soo Jung, Dwivedi Hari P, Moore Matthew D, Escudero-Abarca Blanca I, Jaykus Lee-Ann
Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA.
Functional Food Research Center, Korea University, Seoul, South Korea.
Anal Biochem. 2018 Sep 15;557:27-33. doi: 10.1016/j.ab.2018.04.009. Epub 2018 Apr 10.
A single stranded (ss) DNA aptamer, specific to members of Listeria genus, was used to develop a two-site binding sandwich assay for capture and detection of L. monocytogenes. Antibody-immobilized immunomagnetic beads were used to capture L. monocytogenes, followed by their exposure to the aptamer detector. Detection was achieved by amplification of cell-bound aptamers by qPCR. The lower limit of detection for the combined assay was 2.5 CFU L. monocytogenes in 500 μl buffer. This is juxtaposed to a detection limit of 2.4 log CFU in 500 μl buffer for immunomagnetic separation coupled with qPCR detection of L. monocytogenes targeting the hly gene. When applied to turkey deli meat, subjected to 24 h of non-selective enrichment, the two-site binding sandwich assay showed positive results at initial inoculum levels of 1-2 log CFU per 25 g sample. Because of its lower limit of detection, the assay reported here could be useful for detection of L. monocytogenes in foods and environmental samples.
一种对李斯特菌属成员具有特异性的单链（ss）DNA适配体，被用于开发一种双位点结合夹心检测法，用于捕获和检测单核细胞增生李斯特菌。固定有抗体的免疫磁珠用于捕获单核细胞增生李斯特菌，随后将其暴露于适配体检测器。通过qPCR扩增细胞结合的适配体来实现检测。该联合检测法的最低检测限为500μl缓冲液中2.5 CFU单核细胞增生李斯特菌。相比之下，针对hly基因的单核细胞增生李斯特菌的免疫磁珠分离结合qPCR检测法在500μl缓冲液中的检测限为2.4 log CFU。当应用于经过24小时非选择性富集的火鸡熟食肉时，双位点结合夹心检测法在每25 g样品初始接种水平为1 - 2 log CFU时显示出阳性结果。由于其较低的检测限，本文报道的检测法可能有助于检测食品和环境样品中的单核细胞增生李斯特菌。
