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United States Department of Agriculture

Agricultural Research Service

Research Project: DAIRY MANAGEMENT PRACTICES AND THE TRANSMISSION OF ZOONOTIC PATHOGENS IN MILK Title: Using Molecular Typing to Characterize Bacterial Pathogens Associated with Dairy Farm Environment

Authors
item Hare Jr, William
item Hohn, Christina
item Higgins, James

Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2006
Publication Date: October 12, 2006
Citation: Hare Jr, W.R., Hohn, C.A., Higgins, J.A. 2006. Using molecular typing to characterize bacterial pathogens associated with dairy farm environment [Abstract]. 49th Annual Conference of the American Association of Veterinary Laboratory Diagnosticians, October 12-18, 2006. Minneapolis, MN. p. 166.

Technical Abstract: The dairy farm environment poses special concerns for animal health practitioners, due to the close proximity of the cattle, the presence of other wild and domestic animals in the environment, and the manipulations associated with milking operations. For research-oriented diary farms, such as that at the Beltsville Agricultural Research Center in Beltsville, Maryland, these potential problems are compounded by the regular employment of challenge infections in select animals as part of transgenic and vaccinated animal studies. As part of our efforts to improve and modernize our Herd Health initiative, we are utilizing molecular biology-based approaches for identication and characterization of bacterial pathogens. For S. aureus, spa typing protocols have determined that only two strains, both associated with experimental infections, are circulating in our animals; outside sources play no role in the dissemination of S. aureus in our herd. E. coli genotyping has revealed that most of the isolates present in milk, manure, and internal tissues among dairy cattle at BARC are genotypes B1, B2, and A; genotype D, which includes E. coli O157:H7, is rarely present. Another PCR-based genotyping technique has demonstrated that two distinct clades of B. pumilus were responsible for a lethal, iatrogenic infection in a cow participating in a S. aureus immunity study. Overall, employment of bacterial genotyping assays has permitted us to better understand the local epidemiology of infectious agents in our dairy farm environment, and consequently, improved efforts to ameliorate and control disease outbreaks.

Last Modified: 9/29/2014
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