E. Coli O15:h7 and Cattle: Genetic Characterization of the Host-Bacteria Interaction
It is well accepted that eliminating E. coli O157:H7 from cattle will reduce human foodborne illness with this microbe, but despite decades of research, an effective intervention to stop cattle from carrying E. coli O157:H7 is not known. Understanding the fundamental science that underlies the host:bacteria relationship is requisite to developing effective intervention strategies. The objective of this proposal is to increase our understanding of the food-borne pathogen E. coli O157:H7 and its relationship with cattle so that better intervention strategies can be developed. Our goal is to characterize the gene expression that allows E. coli O157:H7 to persist in cattle. The recognition of the bovine recto-anal junction mucosa as an E. coli O157:H7 colonization site, and the extraordinary situation that this site is easily accessible in live
animals, has allowed us (with previous USDA-NRICGP funding) to develop a reproducible infection model, a culture technique that is superior to fecal culture, and to recover E. coli O157:H7 ex vivo without bacterial division in the laboratory. In this new work we will (1) determine if specific E. coli O157:H7 genes involved in human disease are also involved in colonization of cattle and, (2) use DNA microarray technology to study both bacterial and bovine gene expression during the host:bacteria interaction.