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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: Diversity of Escherichia coli in a Dairy Farm

Authors
item Son, Insook
item Van Kessel, Jo Ann
item Karns, Jeffrey

Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 20, 2008
Publication Date: June 4, 2008
Citation: Son, I., Van Kessel, J.S., Karns, J.S. 2008. Diversity of Escherichia coli in a Dairy Farm. The American Society for Microbiology 108th General Meeting in Boston, Massachusetts, June 1-5, 2008.

Technical Abstract: Dairy cattle are known reservoirs of pathogenic E. coli, but little is known about the dynamics of E. coli in dairy cows or within the dairy farm environment. This study was conducted to determine the relationships between E. coli in water, feces, and manure composites from a dairy farm using pulsed field gel electrophoresis (PFGE). Water from 4 different sampling sites, feces from 15 cows, and manure composite samples from 5 different sampling sites were collected on Dec., 2005 and Dec., 2006. E. coli isolates were characterized by phenotypic testing and confirmed through gadAB-specific PCR. PFGE analysis of XbaI-digested genomic DNA from 530 E. coli isolates from water (n=80), manure composites (n=150), and feces (n=300) resulted in 171 unique restriction digestion patterns (RDPs) based upon cluster analysis using 100% Dice similarity in conjunction with unweighted pair group method with arithmetic mean. The E. coli isolates from water, manure composite, and fecal samples were clustered in 35 RDPs, 73 RDPs, and 87 RDPs, respectively. For fecal samples, cluster analysis generally showed that there was little diversity of isolates from individual cows, however high diversity was observed between animals. In general, there was more diversity within the water and composite samples than was observed in the fecal samples. Some RDPs were common to multiple sample types. Although there were common RDPs between the 2005 and 2006 samplings, the E. coli populations were overall quite distinct between these two sampling times. These results demonstrate a high degree of diversity for E. coli within a dairy farm.

Last Modified: 10/20/2014
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