The purpose of this research is to investigate the ecology of foodborne zoonotic pathogens in dairy cattle including the emergence and dissemination of antimicrobial-resistant strains. A combination of field and laboratory investigations will be used to determine risk factors for the occurrence and transmission of organisms and the genetic relatedness of isolates from animal and human sources. Specific project objectives include developing a communications model to improve the implementation of disease control measures on farms, determination of the role of replacement heifer rearing practices on the emergence and dissemination of multi-drug resistant enteric organisms and molecular characterization of cattle and human isolates. Results will benefit dairy producers by providing information needed to improve management practices and the public by helping to decrease the risk of infection by zoonotic pathogens. The results will be disseminated through continuing education meetings, undergraduate and veterinary education, and publication.
Non-Technical Summary: Domestic livestock are an important source of zoonotic foodborne pathogens including antimicrobial-resistant strains that may represent greater risks to human health. For example, dairy cattle have been implicated as a potential source of drug resistant Salmonella strains that cause infections in people. Reducing the frequency of pathogens on farms reduces the risk of direct exposure or transmission in food or water. The purpose of this research is to identify dairy farm management practices that contribute to the emergence and dissemination of zoonotic pathogens. On-farm and laboratory studies will be used to study the conditions in which bacterial strains develop resistance, transfer of resistance between bacterial strains, and the genetic relationships among bacteria. These results will be used to educate livestock producers, farm workers, and veterinarians in methods to reduce human health risks from pathogenic bacteria. <P> Approach: Commercial dairy farms will be enrolled in the study. The communications objective will be met by using owner, manager and employee interviews to investigate information flow on large commercial farms. This information will be used to develop a communications model that will be tested in a randomized field trial. The role of calf rearing and heifer raising practices will be investigated in a series of field clinical trials and observational studies. Results will be analyzed and incorporated in educational programs. The success of the project will be evaluated by soliciting feedback from program participants.