Escherichia coli O157:H7 is a major food borne human pathogen causing disease worldwide. Cattle have been recognized as the primary reservoir for this pathogen. Healthy cattle (non-shedders) transiently host E. coli O157:H7 in their gastrointestinal tract, with the bacteria mainly residing in the rectum of the large intestine. Transmission of this pathogen among cattle and in the feedlot environment is dependent on shedding load and frequency of E. coli O157:H7 which varies greatly among individual cattle. To address these challenges, the objectives of this proposal are to identify and develop novel bioactive compounds for the control of E. coli O157:H7 and other pathogens in cattle. Additionally, the team will craft innovative mitigation strategies based on the understanding gained from evaluating the microbial ecology as cattle shed E. coli O157:H7 to inform industry practices. To accomplish these objectives, this project will apply functional genomics to the study of the cattle rumen and large intestine metagenomes. The genetic information (e.g., microbial community structure in non-shedders and super-shedders) and bioactive compounds being identified in this study of the genomics of the microbiota of cattle will provide a platform from which to develop mitigation strategies directed at reducing or eliminating E. coli O157:H7 colonization of cattle.