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Title: A NOVEL RELATIONSHIP BETWEEN O-ANTIGEN VARIATION, MATRIX FORMATION, AND INVASIVENESS OF SALMONELLA ENTERITIDIS

Author
item PETTER, JEAN
item KELLER L H - UNIV OF PENNSYLVANIA
item RAHMAN, MAHBUBUR - UNIVERSITY OF GEORGIA
item CARLSON, RUSSELL - UNIVERSITY OF GEORGIA
item Silvers, Sandra

Submitted to: Epidemiology and Infection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Outbreaks of Salmonella enteritidis (SE) in people, who contract the illness by consumption of contaminated eggs and poultry meat, has led to increased interest in vaccinating chicken flocks in an attempt to break the cycle of infection to humans through food. However, success at providing protection to humans by wide scale vaccination of chickens will most likely be limited if vaccines provide greater protection against variants of SE that do not cause contamination of food products. Over time, perhaps in years, disease-causing and food contaminating (virulent) strains could build up in the chicken environment so that significant breaks in protection will begin to occur, which is a situation analagous to the development of antibiotic resistance by bacteria. While on the surface it may appear that this is an argument against vaccination, we present data that suggests that environments can not only be monitored for emerging virulent SE variants with simple assays, but that environments can be managed to decrease the prevalence of virulent SE variants. Thus vaccination together with monitoring and managing environments to decrease virulent SE could be an effective partership that will aid in the abolishment of this pathogen from food sources.

Technical Abstract: Salmonella enteritidis variants, characterized for virulence in chicks and hens, were used to assess the effects of culture ageing, maximal cell concentration, and growth in complement at high temperature on the production of colonial phenotypes. In particular, the effects of growth conditions on a variant producing an extracellular biofilm composed primarily of lipopolysaccharide O-antigen aggregated with unassembled flagellin were evaluated. While most stresses increased the percentage of O-antigen deficient phenotypes, growth in complement at 46C resulted in maintenance of high O-antigen to core linkage ratios, hyperflagellation, and swarming migration on solid media. Hyperexpressed flagella did not have the g,m epitopes typically found on the monophasic flagella of S. enteritidis. Since variation in colony phenotype directly correlated with increases in the virulence factors lipopolysaccharide and flagella, phenotypic variance can be used to indicate the virulence potential in populations of S. enteritidis that serve as reservoirs for human salmonellosis.