About E. coli Blog
Canadian vaccine to combat E. coli and non-E. coli STECs that cause “hamburger disease”
Anne-Marie Hickey of the University of Saskatchewan’s research communications office wrote an interesting article on the work of David Asper, a graduate student at the University of Saskatchewan.
The veterinary microbiology student’s work, soon to be published, is premised on the idea that humans can be protected from harmful bacteria by vaccinating cattle that are the source of the bacteria. Asper’s work builds on groundbreaking research by his supervisor Andrew Potter, director of the Vaccine and Infectious Disease Organization (VIDO) International Vaccine Centre. Potter’s work led to the first cattle vaccine against E. coli O157, the leading cause of “hamburger disease.” The vaccine prevents the bacteria from attaching to the animal’s intestines and from colonizing, cutting the disease off at the source.
“The E. coli O157 vaccine is the first of its kind worldwide and is expected to significantly lessen the amount of E. coli O157 present in food products and also in the environment,” said Potter. But while E. coli O157 is the most prevalent type of E. coli in North America, it’s just one of hundreds of E. coli bacteria around the world that cause disease by producing shiga toxin. These shiga toxin-producing E. coli (STEC) produce infections that can range from very mild to severe or even life-threatening. “Right now, STEC bacteria is the number one cause of renal (kidney) failure in children around the world,” said Asper. “It affects adults too, but children are the most susceptible.”
STEC bacteria cause disease in humans if meat becomes contaminated during slaughter or if feces mix with groundwater, polluting drinking or swimming water or food supplies. But the STEC bacteria that cause human illness generally do not make animals sick so healthy cattle often have STEC bacteria living in their intestines.
Due to improved detection methods, cases of non-O157 E. coli infection are on the rise, increasing the importance of having the second-generation vaccine.
“We can protect humans by vaccinating animals before they come in contact with the pathogen. I think that’s very important work that will lead to a lot fewer infections,” Asper said. His work could help prevent tragedies such as the 2000 incident in Walkerton, Ont. when fecal material from cattle seeped into the water system, contaminating drinking water and resulting in thousands of illnesses and seven deaths in the community.
Just as the E. coli O157 cattle vaccine will be a significant tool for use by beef and dairy producers to mitigate human infection risk, Asper’s vaccine could also lessen financial losses to meat producers. When STEC bacteria is found in just one meat sample, beef processors are required to destroy the entire shipment — a significant cost to farmers.