Award details

Molecular basis of foodborne disease risk of variants of Salmonella Typhimurium DT193 and U288

Reference	BB/M021114/1
Principal Investigator / Supervisor	Professor Mark Stevens
Co-Investigators / Co-Supervisors
Institution	University of Edinburgh
Department	The Roslin Institute
Funding type	Research
Value (£)	123,594
Status	Completed
Type	Research Grant
Start date	01/11/2015
End date	30/06/2019
Duration	44 months

Abstract

The considerable economic and health impact of pathogens of the genus Salmonella is the result of their presence in livestock and poultry, entry into and survival within the food chain, and their ability to cause intestinal or systemic disease. However, not all variants of Salmonella are equally likely to cause disease in man and an understanding of the molecular basis of the likelihood that a particular variant will enter the food chain and cause disease in man is critical to food safety. Some variants of Salmonella are prevalent in food animals yet are not a predominant cause of human clinical infections. This research proposal seeks to address these questions using a molecular epidemiology and comparative whole genome sequence approach combined with classical molecular biology and infection models to compare two highly related variants of S. Typhimurium (DT193 and U288) that exhibit distinct risk profiles for foodborne disease in man, despite similar epidemiology in livestock. Little is known about the variation in genotype and phenotype of closely related variants of bacterial pathogens circulating in zoonotic reservoirs and the environment. Crucially, genotypic polymorphisms are not only potential candidate targets for intervention strategies aimed at decreasing the likelihood that these pathogens enter the food chain but also targets for distinguishing variants of pathogens that differ in their risk to food safety, useful for surveillance. This study will define the molecular epidemiology of common variants of Salmonella Typhimurium in the UK pig herds and those entering the food chain via abattoirs by analysis of whole genome sequence variation. Genotypic, transcriptomic and phenotypic variation will be determined and important genotypic differences understood in the context of their associated phenotype by whole genome recombination and mutagenesis approaches.

Summary

The bacterium Salmonella accounts for about 125 million incidents of disease worldwide each year, and nearly a million deaths. The morbidity and mortality caused by this pathogen has a significant impact on the economies of both resource rich and resource poor countries. Most cases of non-typhoidal Salmonella are thought to result from fecal contamination of food and food products, either directly in the food chain or by cross contamination in the home or restaurants. A common and therefore critical step for this is the entry of the bacterium into the food chain from livestock and poultry in which this pathogen is commonly found. However, even though virtually all types of Salmonella have the potential to cause disease in man, not all are commonly associated with disease in man. Understanding how these processes work is critical to the detection of high risk types of Salmonella in livestock and the food chain, and efforts to decrease the likelihood of Salmonella entering these environments. We propose to study two common types of Salmonella that are both present in pig herds butter present distinct risk to food safety. We will study these bacteria at a genetic and behavioural level to understand how the different types circulate in pig populations in the UK and how they enter and survive in our food. First a collection of pig and food chain isolates of Salmonella Typhimurium will be whole genome sequenced and the variation in their genome used to define the how they spread into the food chain and into the human population. Then we will study important behavioural variations that may impact the threat posed by the variants in food. As the types of Salmonella to be studied are genetically closely related, the number of genetic differences are small, which makes it possible to identify candidate differences associated with altered behaviours of the variants. Genetic differences in types of Salmonella are potential candidates targets for surveillance to identify types more likely to represent a risk to food safety or for other intervention strategies aimed at decreasing the likelihood that they will enter the food chain.

Impact Summary

Please see documents submitted by lead RO (joint reference Q2094507).

Committee	Research Committee A (Animal disease, health and welfare)
Research Topics	Animal Health, Microbial Food Safety, Microbiology
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

Associated awards:

BB/M025411/1 Molecular basis of foodborne disease risk of variants of Salmonella Typhimurium DT193 and U288

BB/M025489/1 Molecular basis of foodborne disease risk of variants of Salmonella Typhimurium DT193 and U288

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