Salmonella enteritidis: Virulence factors and invasive infection in poultry

Worldwide, Salmonella enteritidis is a clinically prevalent Salmonella serotype, which is associated with the consumption of foods containing eggs or poultry meat from systemically infected chickens. Several factors, including lipopolysaccharide structure, plasmid carriage and the expression of fimbriae, have been investigated in relation to their roles in pathogenicity. While each of these factors has been linked to virulence in different hosts, most have been discounted as playing a part in the systemic colonization of poultry. It is possible that recent acquisition of virulence factors, in combination with existing mechanisms, has contributed to the development of systemic infection with S. enteritidis and its consequent prevalence in poultry. The expression of certain fimbrial structures appears to be linked most strongly with systemic colonization in chickens, although the expression of other factors is necessary for infection.