Favrin S J, Jassim S A, Griffiths M W
Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Appl Environ Microbiol. 2001 Jan;67(1):217-24. doi: 10.1128/AEM.67.1.217-224.2001.
Salmonella is the second-leading cause of food-borne illness in most developed countries, causing diarrhea, cramps, vomiting, and often fever. Many rapid methods are available for detection of Salmonella in foods, but these methods are often insensitive or expensive or require a high degree of technical ability to perform. In this paper we describe development and characterization of a novel assay that utilizes the normal infection cycle of bacteriophage SJ2 for detection of Salmonella enterica serovar Enteritidis in broth. The assay consists of four main stages: (i) capture and concentration of target cells by using immunomagnetic separation (IMS); (ii) infection of the target bacterium with phage; (iii) amplification and recovery of progeny phage; and (iv) assay of progeny phage on the basis of their effect on a healthy population of host cells (signal-amplifying cells). The end point of the assay can be determined by using either fluorescence or optical density measurements. The detection limit of the assay in broth is less than 10(4) CFU/ml, and the assay can be performed in 4 to 5 h. The results of this study demonstrate that the IMS-bacteriophage assay is a rapid, simple, and sensitive technique for detection of Salmonella serovar Enteritidis in broth cultures which can be applied to preenriched food samples.
在大多数发达国家，沙门氏菌是食源性疾病的第二大病因，可引发腹泻、痉挛、呕吐，还常常伴有发热症状。有许多快速方法可用于检测食品中的沙门氏菌，但这些方法往往不够灵敏、成本高昂，或者需要较高的技术能力才能操作。在本文中，我们描述了一种新型检测方法的开发与特性，该方法利用噬菌体SJ2的正常感染周期来检测肉汤中的肠炎沙门氏菌血清型肠炎亚种。该检测方法包括四个主要阶段：（i）通过免疫磁珠分离（IMS）捕获和浓缩目标细胞；（ii）用噬菌体感染目标细菌；（iii）扩增和回收子代噬菌体；（iv）根据子代噬菌体对健康宿主细胞群体（信号放大细胞）的影响来检测子代噬菌体。该检测方法的终点可以通过荧光或光密度测量来确定。该检测方法在肉汤中的检测限低于10⁴CFU/ml，检测可在4至5小时内完成。本研究结果表明，IMS-噬菌体检测方法是一种快速、简单且灵敏的技术，可用于检测肉汤培养物中的肠炎沙门氏菌血清型肠炎亚种，并且可应用于预增菌的食品样本。
