E. coli is a large, diverse group of bacteria often found in the intestines of humans and animals. While most strains are harmless, some can cause mild to fatal illnesses. E. coli has been widely associated with several foodborne illness outbreaks worldwide. In the United States alone, E. coli is responsible for approximately 100,000 illnesses, 3,000 hospitalizations, and 90 deaths annually.
One of the biggest challenges in the fight against E. coli is that its pathogens constantly evolve or acquire new characteristics that make them more resistant to antibiotics. In an evolutionary arms race at the molecular level, MSU is finding ways to protect people with new vaccines by forecasting how these pathogens will change. By maintaining a timely advantage, MSU researchers are equipped to develop the strategies needed to protect the world from the potentially devastating consequences of E. coli.
A recent study at MSU found that dairy cattle under stress from hot weather and energy loss from milk production were more likely to shed the Shiga toxin–producing E. coli, also known as STEC. Cattle are common carriers of STEC, and food or water contaminated with cattle feces is a common source of E. coli infections in humans.
The MSU study sampled more than 1,000 cattle from six dairy farms and five feedlots in Michigan.
“Most importantly, our study involved cattle farmers who were willing to be involved in projects that help to improve the safety and quality of the food they produce,” said Dan Grooms, MSU large animal veterinarian and a collaborator in the study.
“Reducing STEC colonization and shedding in cattle can decrease the likelihood of these bacterial pathogens from entering the food supply and causing foodborne infections in people,” said Shannon Manning, MSU molecular biologist and principal investigator of the study. “By understanding specific factors that increase the risks of STEC shedding in cattle, new management strategies, such as the isolation of high-risk animals, can be developed to limit transmission.”
MSU researchers—including microbiologists, epidemiologists, animal scientists, veterinarians, farmers, and students—will continue to examine the diversity of different STEC strains that are shed and determine the rate at which animals acquire new STEC strains over time.
“We hope to assess how frequently individual animals acquire different types of STEC and determine which types are most commonly linked to disease in humans,” Manning said. “It would have been extremely difficult to do this study without such a wide range of expertise.”
This research occurs at MSU’s Thomas S. Whittam STEC Center, and important national resources. MSU’s STEC Center manages the national sampling of E. coli specimens. It serves as the repository for specimens, distributes sets of reference strains for use by investigators, and provides researchers with a standard reference collection of wellcharacterized strains and central on-line databases.