Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples

<i>Salmonella</i> spp. is one of the most important foodborne pathogens worldwide. Given the fact that poultry and poultry products are the main source of human infection, Salmonella control in these farms is of utmost importance. To better control this pathogen in farms, boot swabs are...

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Main Authors: Patricia Regal, Anne Doval, Iria García-Ramos, Alberto Cepeda, Alejandro Garrido-Maestu, Alexandre Lamas
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/13/24/4069
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author Patricia Regal
Anne Doval
Iria García-Ramos
Alberto Cepeda
Alejandro Garrido-Maestu
Alexandre Lamas
author_facet Patricia Regal
Anne Doval
Iria García-Ramos
Alberto Cepeda
Alejandro Garrido-Maestu
Alexandre Lamas
author_sort Patricia Regal
collection DOAJ
description <i>Salmonella</i> spp. is one of the most important foodborne pathogens worldwide. Given the fact that poultry and poultry products are the main source of human infection, Salmonella control in these farms is of utmost importance. To better control this pathogen in farms, boot swabs are used to sample farm environments but the analysis of these swabs is mainly based on culture-dependent methods. In the present study, a novel loop-mediated isothermal amplification (LAMP) method was developed for the rapid screening of <i>Salmonella</i> spp. in boot swab samples from broiler flock environments. Four different DNA extraction protocols were evaluated in depth, including a simple thermal lysis, a chelex-based protocol and two thermal lysis protocols followed by the purification of magnetic beads made of silica (“glass milk”) in order to determine the most suitable alternative for potential on-site, farm analyses. The methodology evaluation included a blind interlaboratory assay and as a proof-of-concept, a naked-eye colorimetric assay was also included. Following the final methodology, it was possible to reach an LoD<sub>50</sub> of 1.8 CFU/25 g of the samples, with a high relative sensitivity (95.7%), specificity (100%) and accuracy (96.6%) along with Cohen’s kappa of concordance with respect to the ISO standard 6579-1:2017 of 0.9, with an RLOD of 1.3. In addition to this, due to the relevance of certain serotypes with the genus <i>Salmonella</i> spp., a serotype LAMP panel for the specific identification of <i>S.</i> Typhimurium, <i>S.</i> Enteritidis, <i>S.</i> Infantis, <i>S.</i> Hadar and <i>S.</i> Virchow was also developed. Even though some degree of cross-reactivity among the primers developed was observed, all the serotypes could be accurately identified based on their melt curve analysis profile. Taken together, in the present study, a rapid <i>Salmonella</i> spp. screening method, suitable for farm applications, was developed, along with a serotyping panel that could be used in a laboratory setup for the identification of the most relevant serotypes of the genus, taking advantage of real-time amplification followed by melt curve analysis.
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spelling doaj-art-d6f9a4c0653a499ba9db42847515d5692024-12-27T14:26:25ZengMDPI AGFoods2304-81582024-12-011324406910.3390/foods13244069Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock SamplesPatricia Regal0Anne Doval1Iria García-Ramos2Alberto Cepeda3Alejandro Garrido-Maestu4Alexandre Lamas5Food Hygiene, Inspection and Control Laboratory (LHICA-USC), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, Campus Terra, Universidade de Santiago de Compostela (USC), 27002 Lugo, SpainFood Hygiene, Inspection and Control Laboratory (LHICA-USC), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, Campus Terra, Universidade de Santiago de Compostela (USC), 27002 Lugo, SpainFood Hygiene, Inspection and Control Laboratory (LHICA-USC), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, Campus Terra, Universidade de Santiago de Compostela (USC), 27002 Lugo, SpainFood Hygiene, Inspection and Control Laboratory (LHICA-USC), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, Campus Terra, Universidade de Santiago de Compostela (USC), 27002 Lugo, SpainLaboratory of Microbiology and Technology of Marine Products (MicroTEC), Instituto de Investigaciones Marinas (IIM—CSIC), Eduardo Cabello, 6, 36208 Vigo, SpainFood Hygiene, Inspection and Control Laboratory (LHICA-USC), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, Campus Terra, Universidade de Santiago de Compostela (USC), 27002 Lugo, Spain<i>Salmonella</i> spp. is one of the most important foodborne pathogens worldwide. Given the fact that poultry and poultry products are the main source of human infection, Salmonella control in these farms is of utmost importance. To better control this pathogen in farms, boot swabs are used to sample farm environments but the analysis of these swabs is mainly based on culture-dependent methods. In the present study, a novel loop-mediated isothermal amplification (LAMP) method was developed for the rapid screening of <i>Salmonella</i> spp. in boot swab samples from broiler flock environments. Four different DNA extraction protocols were evaluated in depth, including a simple thermal lysis, a chelex-based protocol and two thermal lysis protocols followed by the purification of magnetic beads made of silica (“glass milk”) in order to determine the most suitable alternative for potential on-site, farm analyses. The methodology evaluation included a blind interlaboratory assay and as a proof-of-concept, a naked-eye colorimetric assay was also included. Following the final methodology, it was possible to reach an LoD<sub>50</sub> of 1.8 CFU/25 g of the samples, with a high relative sensitivity (95.7%), specificity (100%) and accuracy (96.6%) along with Cohen’s kappa of concordance with respect to the ISO standard 6579-1:2017 of 0.9, with an RLOD of 1.3. In addition to this, due to the relevance of certain serotypes with the genus <i>Salmonella</i> spp., a serotype LAMP panel for the specific identification of <i>S.</i> Typhimurium, <i>S.</i> Enteritidis, <i>S.</i> Infantis, <i>S.</i> Hadar and <i>S.</i> Virchow was also developed. Even though some degree of cross-reactivity among the primers developed was observed, all the serotypes could be accurately identified based on their melt curve analysis profile. Taken together, in the present study, a rapid <i>Salmonella</i> spp. screening method, suitable for farm applications, was developed, along with a serotyping panel that could be used in a laboratory setup for the identification of the most relevant serotypes of the genus, taking advantage of real-time amplification followed by melt curve analysis.https://www.mdpi.com/2304-8158/13/24/4069loop-mediated isothermal amplification<i>Salmonella</i> spp.<i>S.</i> Typhimurium<i>S</i>. Enteritidis<i>S</i>. Infantis<i>S</i>. Hadar
spellingShingle Patricia Regal
Anne Doval
Iria García-Ramos
Alberto Cepeda
Alejandro Garrido-Maestu
Alexandre Lamas
Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
Foods
loop-mediated isothermal amplification
<i>Salmonella</i> spp.
<i>S.</i> Typhimurium
<i>S</i>. Enteritidis
<i>S</i>. Infantis
<i>S</i>. Hadar
title Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
title_full Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
title_fullStr Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
title_full_unstemmed Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
title_short Loop-Mediated Isothermal Amplification-Based Workflow for the Detection and Serotyping of <i>Salmonella</i> spp. in Environmental Poultry Flock Samples
title_sort loop mediated isothermal amplification based workflow for the detection and serotyping of i salmonella i spp in environmental poultry flock samples
topic loop-mediated isothermal amplification
<i>Salmonella</i> spp.
<i>S.</i> Typhimurium
<i>S</i>. Enteritidis
<i>S</i>. Infantis
<i>S</i>. Hadar
url https://www.mdpi.com/2304-8158/13/24/4069
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