E. coli Lives in Cattle

E. coli lives in the gastrointestinal tract of cattle and is shed in manure. The manure then spreads onto animal hides, into farm environments, drinking water for animals, and irrigation water and soil used for growing crops.

The Centers for Disease Control and Prevention estimates some 100,000 cases of foodborne illness are linked to enterohemorrhagic E. coli each year.

Funded in part by the Food and Drug Administration, the UGA probiotic culture studies involved feeding calves and grain-fed steers a mixture of beneficial bacteria.

Searching for Beneficial Bacteria

"We examined about 1,200 bacteria isolated from cattle that didn't carry E. coli O157:H7," said Dr. Michael P. Doyle, Director of the CFS. "We looked for beneficial bacteria that prevent E. coli O157:H7 from being carried in the intestinal tract of cattle."

The resulting probiotic bacteria was fed to ruminating calves and adult cattle. The effect of this treatment was a major reduction in carriage and fecal shedding of enterohemorrhagic E. coli and elimination of E. coli O157:H7 from 80 to 90 percent of the treated cattle.

Reducing E. coli in Cattle Reduces Human Risks, Too

"As best we know, cattle are the principal source of enterohemorrhagic E. coli," said Doyle. "By reducing the amount of harmful E. coli they carry, we can reduce the environmental exposure of people to these pathogens."

Most E. coli O157:H7-related illnesses can be traced back to eating undercooked hamburgers but exposure to cattle manure on the farm is also a contributing factor, said Doyle.

"More and more we are seeing that food is not the sole vehicle that carries enterohemorrhagic E. coli," he said. "Being exposed to animals, primarily cattle, and their manure is an important factor."

Cases Linked to Farm and Petting Zoo Visits

Ruminating animals like cattle, goats, deer and sheep are considered the primary carriers of E. coli O157:H7, said Doyle.

Visits to farms and petting zoos continue to be linked to outbreaks of E. coli illnesses. "People have to remember that these animals often lie on their manure which clings to their hair and hides," said Doyle. "A recent outbreak in Pennsylvania where several children were infected by E. coli was associated with a farm visit."

Doyle says the traditional method of vaccinating animals to prevent E. coli O157:H7 carriage does not prevent the animal from shedding the E. coli in feces. "Our new probiotic treatment shows great promise in this area," he said.

UGA has received a patent for the cultures and the new method now awaits FDA review and approval to commercialize the cultures as an available treatment.

(Article by Sharon Omahen - UGA CAES Education, Communication and Technology Unit.)