Cattle vaccine works to reduce E. coli O157:H7

A commercial vaccine for cattle can effectively reduce levels of E. coli by more than 50% according to a Kansas State University study. The vaccine is also effective using two doses instead of the recommended three doses, which can help cut costs for the beef industry.

David Renter, associate professor of epidemiology, is the principal investigator on a project that researched the effectiveness of products used to prevent the shedding of E. coli O157:H7 in cattle. The research appears in an online version of the journal Vaccine and helps improve current preventative methods for addressing food safety concerns.

While E. coli O157:H7 does not affect cattle, it causes foodborne disease in humans. Vaccines and other products may be given to cattle to help prevent the spread of the bacteria.

“We wanted to test how well these products work to control E. coli O157:H7 in a commercial feedlot with a large population of cattle that were fed in the summer and may be expected to have a high level of E. coli O157:H7,” Renter said.

Using a commercial feedlot setting, the researchers studied more than 17,000 cattle during an 85-day period. They studied two products: a vaccine and a low-dose, direct-fed microbial.

“What's unique about this study is the number of animals we used, the research setting and that we used commercial products in the way that any cattle producer could use them,” Renter said. “We didn't want it to be any different than the way somebody would use the products in a commercial feedlot.”

The researchers found that the vaccine reduced the number of cattle that were shedding E. coli O157:H7 in faeces by more than 50%. E. coli shedding was reduced by more than 75% among cattle that were high shedders of E. coli. While the vaccine label suggests that it is given in three doses, the researchers found that two doses of the vaccine significantly reduced E. coli.

“Showing that level of efficacy with two doses is really important because a shift to two doses from three could significantly cut costs for the beef industry,” Renter said. “In terms of logistics, it can be difficult for commercial feedlot production systems to vaccinate animals three times. Both of these benefits help when considering how the vaccine can be adopted and implemented in the industry.”

The researchers also discovered that the low-dose, direct-fed microbial product did not work as well as the vaccine. Renter said while the study used a lower dose of the direct-fed microbial and could find no evidence that it reduced E. coli shredding, it is possible that the direct-fed microbial product is more effective at a higher dose.

“This vaccine is an option for reducing E. coli,” Renter said. “We have shown that this vaccine works and that it is a tool that could be adopted in the industry.”