Review of the Food-borne Zoonoses Research ... - ARCHIVE: Defra

Project code: OZ0319
Project title: Salmonella pathogenesis in cattle and pigs
Start date (dd/mm/yy): 01/07/2002
End date (dd/mm/yy): 30/09/2006
£709,200
Total cost:
Affiliation: Institute for Animal Health, Compton
Sub-contractor(s): None
Abstract of research
Salmonella enterica is an enteric bacterial pathogen of worldwide importance. Over
2500 distinct serovars of S. enterica exist and these can be divided into three broad
types; ubiquitous serovars that can cause acute but self-limiting gastroenteritis in a broad
range of hosts (e.g. S. Typhimurium), host-restricted serovars that exhibit a preference
for a narrower range of hosts (e.g. S. Dublin and S. Choleraesuis) and host-specific
serovars that produce disease in only one host (e.g. S. Typhi in humans). Host-restricted
and -specific serovars often cause only mild enteritis but possess the ability to
disseminate from the intestines to the organs of the body, causing typhoid fever-like
illnesses in animals that may be severe and life-threatening. Non-typhoidal Salmonellosis
caused by ubiquitous serovars also poses serious welfare and economic problems for
livestock producers. Moreover, Salmonella infection of pigs and cattle can lead to entry of
the pathogen into the food chain and environment, providing an important reservoir of
human infection. The molecular mechanisms underlying the ability of Salmonella enterica
to colonise the intestines of food-producing animals, induce enteritis and in some cases
translocate to distal sites, are poorly understood. Defra-funded research conducted
under project OZ0319 aimed to understand these processes in greater detail and to use
the knowledge to develop, test and refine novel methods of disease control. Such
research led to the testing of subunit vaccines in pigs, live-attenuated vaccines in calves
and analysis of the protective efficacy of small molecule inhibitors that disarm a key
Salmonella virulence factor.
Review Summary
Innovative and novel methodologies were used to examine the pathogenesis of
salmonella in cattle and pigs, including factors that play conserved roles in colonisation of
calves, pigs and chickens, and host-specific colonisation factors. The researchers
identified cytokine responses of the intestinal mucosa following infection with S.
Typhimurium and the host-specific serovars, S. Dublin and S. Choleraesuis. The project
included an examination of the basis of attenuation of mutant strains in vitro and in
animals. The researchers further examined the efficacy of a subunit vaccine that
comprised S. Typhimurium Type III secreted proteins in pigs, and the ability of smallmolecule
inhibitors of Type III secretion to block Salmonella-induced Enteritis.
Although the study has increased background knowledge, for this project to be really
relevant to Defra, it also needed to attract the interest and funding of the wider
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