The objectives of this proposed research will be to identify naturally occurring
genetic variation in Salmonella enterica that correlates with the evolution of egg
contamination and enhanced growth of the bacterium in the hen, the egg and in the on-
farm environment and to then determine how different genetically defined strains vary
in their pathobiology within the hen and how these differences affect the risk of egg
contamination and the control of disease.
Approach: Our approach will be to identify single nucleotide polymorphisms (SNPs) that occur
naturally in the genome of Salmonella enterica, link them to the phenotypic
attributes of the pathogen that are relevant to causation of egg contamination and
growth to high cell density, and develop a phylogenetic database that aids cost
effective screening of the Salmonellae for these traits. We will then characterize
the processes by which bacteria are deposited inside eggs laid by infected laying
hens and assess the significance of these processes for proposed cost effective and
feasible disease control measures such as egg refrigeration, diagnostic egg
culturing, and assay of shell quality.