Improvement of Loop-Mediated Isothermal Amplification Combined with Chromatographic Flow Dipstick Assay for Salmonella i
- PDF / 555,133 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 21 Downloads / 182 Views
Improvement of Loop-Mediated Isothermal Amplification Combined with Chromatographic Flow Dipstick Assay for Salmonella in Food Samples Jia Yu 1 & Jiahua Xing 2 & Xijing Zhan 3 & Zhen Yang 2 & Jun Qi 3 & Yuxi Wei 1 & Yin Liu 2 Received: 30 August 2019 / Accepted: 15 April 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Loop-mediated isothermal amplification (LAMP) had been employed as a powerful tool to facilitate genetic tests for various food pathogens, as it is easy to perform. Recently, various methods of detecting the LAMP amplicon were developed. In this study, we improved two LAMP assays by combining LAMP with chromatographic flow dipstick (LFD) assays for Salmonella (targeting phoP and invA, respectively). We evaluated different labeled primer sets, then selected the optimal sets to perform the LFD assays. We compared the optimal LFD and LAMP assays with the ISO standard method. The results showed that LFD was more sensitive and quicker than LAMP. Furthermore, enrichment broths of 225 food samples were tested. The sensitivity of two LFD assays was 100%. The specificity of LFD assay targeting phoP was 99.1%, and LFD assay targeting invA was 99.5%. For the LFD assay targeting phoP, the estimate of limit of detection (LOD) 50% was 0.061 CFU/g and the estimate of LOD 95% was 0.265 CFU/g. For the LFD assay targeting invA, the estimate of LOD 50% was 0.040 CFU/g and the estimate of LOD 95% was 0.172 CFU/g. We validated this method in a primary laboratory, where we accomplished the assay only using an incubator and a heating block. It suggested that the LFD assay had the potential to become a suitable diagnostic method in field test and primary labs. Keywords Loop-mediated isothermal amplification . Chromatographic flow dipstick . Salmonella . phoP . invA
Introduction Salmonella is an important foodborne pathogen for the public health (Gomez et al. 1997; Sanchez-Vargas et al. 2011). It was estimated that 21 million people were infected by Salmonella every year worldwide (Crump and Mintz 2010). The World Health Organization mentions Salmonella as one of the four crucial global causes of diarrheal diseases. Undercooked food, including various meats, fruits, and vegetables, can be Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12161-020-01760-0) contains supplementary material, which is available to authorized users. * Yin Liu [email protected] 1
College of Life Sciences, Qingdao University, Qingdao 266071, People’s Republic of China
2
School of Medicine, Nankai University, Tianjin 300071, People’s Republic of China
3
Tianjin International Travel Health Care Center, Tianjin 300456, People’s Republic of China
contaminated with the pathogen during the lengthy farm-tofork process and transmit it to humans (Park et al. 2012; Pires et al. 2010). Therefore, multifaceted detection methods of Salmonella are needed to better ensure food safety, especially during the production, processing, and distribution of agricultural food. These
Data Loading...
