NRC Institute for Biological Sciences

Targeting the Source: Eliminating E.coli O157:H7 from the Digestive Systems of Cattle

Advance
In an effort to prevent another tragedy such as the one that took place in Walkerton, Ontario in 2000, NRC's Institute for Biological Sciences has joined forces with Calgary-based Dow AgroSciences Canada Inc. to develop a natural antibody that would lead to the elimination of E.coli O157:H7 in the digestive tracts of cattle.

Background
Research began 20 years ago when scientists realized that people were getting sick from a dangerous strain of E.coli O157:H7 that was present in undercooked hamburger meat. The source of the problem turned out to be in the cow's gut, a normal incubating environment for the bacteria. More recently, the E.coli 0157:H7 bacterium has been of concern because of its appearance in public water systems which, it is believed, were contaminated by run-off from fields treated with manure from infected cows.

Initially, IBS researchers were attempting to develop a quick identification process, which led to the idea to go one step further and eliminate the O157:H7 strain of bacteria altogether. The first option explored was to produce a vaccine that would prevent the multiplication of the toxic bacteria from occurring. This was met with market resistance, as producers were wary of mass immunization. So the research team turned to a feed-based delivery system.

The concept is to express an E.coli 0157:H7 specific antibody in plants and then incorporate the plant-made antibody into animal feed. When coming into contact with the bacteria, the antibody would surround the O157:H7 strain, only preventing it from attaching itself to the cow's stomach lining and therefore inhibiting its growth.

The research holds significant promise for the inclusion of an antibody in cattle feed for the elimination of E.coli 0157:H7 from the cattle digestive system and possibly the elimination of the organism from the entire cattle reservoir.

Impact
"First-generation traits such as herbicide resistance are embraced by the farming community, but for the consumers who are not engaged in farming, the benefits and advantages of what biotech can mean has had no direct effect," said Steve Webb, Dow AgroSciences' Project Success Leader. "This project offers an opportunity to address a need which isn't being addressed. Our partnership with IBS is expected to allow this technology to develop more rapidly into a commercial product."

The public health benefits derived from the elimination of E.coli O157:H7 in cattle are tremendous, leading to a safer consumption of food products and water. By using a natural antibody produced in plants and delivered through cattle feed, a higher acceptance value among both farmers and the general public is expected, leading to a greater likelihood of success.

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