Submitted to: Applied and Environmental Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/24/2004
Publication Date: 5/4/2004
Citation: Bouldin, J.G., Gast, R.K., Humphrey, T.J., Henzler, D.J., Morales, C., Coles, K. 2004. Subpopulation Behavior Of Egg-Contaminating Salmonella Enterica Serovar Enteritidis As Defined By Lipopolysaccharide O Chain. Applied and Environmental Microbiology v.70, p.2756-2763, 2004. Interpretive Summary: Not required.
Technical Abstract: Characterization of Salmonella enterica serovar Enteritidis was refined by incorporating new data from isolates obtained from avian sources, the spleens of naturally infected mice, and from the United Kingdom into an existing lipopolysaccharide (LPS) O-chain compositional database. The probabilities that avian isolates produced high-molecular-mass LPS O chain ranked, from least to greatest, as follows: pooled kidney, liver, spleen < intestine < cecum < ovary and oviduct < albumen < yolk < whole egg. Mouse isolates were most like avian intestinal samples, whereas United Kingdom isolates were most like those from the avian reproductive tract and egg. Non-reproductive tract organ isolates had significant loss of O-chain. Clonally related isolates that varied in their ability to make biofilm and to be orally invasive produced different O-chain structures at 25 but not at 37 degrees C. Hens infected at a 91:9 biofilm-positive/-negative colony phenotype ratio yielded only the negative phenotype from eggs. These results indicate that the environment within the hen applies stringent selection pressure on subpopulations of S. enterica serovar Enteritidis at certain points in the infection pathway that ends in egg contamination. The avian cecum rather than the intestines is the early interface between the environment and the host that supports emergence of subpopulation diversity. These results suggest that diet and other factors that alter cecal physiology should be investigated as a means to reduce egg contamination.