New research shows there may be a way to give cows a built in defense against mastitis-causing pathogens.

An Agricultural Research Service-led team has combined specific DNA segments from two different sources to produce a novel antimicrobial protein. The resulting "fusion" antimicrobial protein works by degrading the cell walls of bacterial pathogens in a solution of whey extracted from cow's milk. Research has shown the fusion protein to be active against Staphylococcus aureus and three streptococcal mastitis pathogens.

Agriculturally, the technology provides a key step to developing dairy cows that have a natural, built-in defense against mastitis — a disease that costs U.S. dairy producers up to $2 billion annually.

In the realm of infectious disease, one way to reduce microbial resistance that results from widespread antibiotic use is to come up with new ways to fight pathogens. The findings from this experimental study were published in the April 2006 issue of Applied Environmental Microbiology and presented at the American Society of Microbiology meeting in Orlando, Fla. in May.

While all milk contains several naturally occurring antimicrobial proteins, such as lysozyme and lactoferrin, the sale of milk containing the fusion protein would first require rigorous food safety testing and federal regulatory approval.

For more from ARS, go to: http://www.ars.usda.gov/is/pr/2006/060524.htm

Agricultural Research Service