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Non-specific and innate resistance to Salmonella infection in chicken and pigs. - OZ0313

Description
The two major sources of Salmonella "food-poisoning" in human population are probably poultry and pigs. Carcass contamination arises largely from the ability of some strains of Salmonella to colonise the alimentary tract of poultry and pigs in the absences of disease but can also follow invasive infection which may, for example, lead to egg contamination. In the absence of effective vaccines control of Salmonella is based on the use of hygenic measures and antibiotics.
The aim of this project is to study two aspects of innate and non-specific resistence which may be developed to provide sustainable biological control methods not requiring the use of antibiotics.
Resistence to invasive Salmonella infection in poultry is mediated by a single gene (Sal1) localised on chromosome 5. This project aims to identify the biological activity controlled by this gene.
Oral administration of live, attenuated Salmonella strains to gnotobiotic pigs confers resistance to challenge by a wild-type strain given 24 hours after the attenuated strain which is based on classical immunity or "competitive exclusion". The second aim of this project is, therefore, to determine the mechanisms involved which could be manipulated to provoke the reponse in the absence of the vaccine.
The research is in support of MAFF policy requirements on food safety and animal health and welfare. The strategies aims are to develop control measures based on natural host defence mechanisms which will reduce dependance on antibiotics and reduce the risk of the development of multiple resistant strains of bacteria.
Objective
The aims of this research are to:
1) Determine the cellular basis for the difference in susceptibility to systemic salmonellosis and localisation in the reproductive tract already demonstrated at IAH in inbred chicken lines.

2) Determine the basis for the stimulation of non-specific immunity in the pig intestine following intestinal colonisation by attenuated Salmonella strains.

This will involve research to:-
1. Identify host cells responsible for the difference in susceptibility including an assessment of the ability of macrophages and to phagocytose and kill Salmonella.
2. Identify cellular and cytokine responses induced in the pig intestine following colonisation by attenuated Salmonella strains and correlate these with in vitro cytokine and invasion assays
Project Documents
• Final Report : Non-specific and innate resistance to Salmonella infection in chickens and pigs   (89k)
Time-Scale and Cost
From: 1999

To: 2002

Cost: £689,400
Contractor / Funded Organisations
Institute for Animal Health (BBSRC)
Keywords
Animal Health              
Biotechnology              
Plants and Animals              
Salmonella              
Transmission              
Zoonoses              
Fields of Study
Animal Health