Scientific Breakthrough Prevents E. coli From Surviving In Cattle
In the continuing battle to prevent naturally occurring microorganisms like E. coli O157:H7 from growing in cattle, researchers have discovered some promising new tools.
Although E. coli O157:H7 can cause illness in humans, the bacteria often exists as part of the gastrointestinal flora in healthy cattle. In turn, microbiologists at the University of Texas (“UT”), Southwestern Medical Center, working with the USDA, uncovered a mechanism which actually prevents E. coli O157:H7 from surviving in grain-fed cattle.
E. coli O157:H7 harbors a gene called sdiA, which makes the SdiA protein. When traveling within a cattle’s body, the SdiA protein senses a chemical made by microbes in the animal's rumen, the first of a cow's four stomachs, which serves as a large fermentation chamber.
Only after detecting this signal will the bacteria pass through the rumen and colonize in the recto-anal junction. By interfering with the SdiA protein (or, the genetic sensor), however, researchers were able to stop the bacteria from ever reaching the required colonization site. Notably, rather than colonizing, the bacteria simply died off, preventing any potential for future shedding or contamination.
"We're diminishing colonization by not letting pathogen go where it needs to go," said Dr. Vanessa Sperandio, associate professor of microbiology and biochemistry at UT Southwestern and senior author of the study. "If we can find a way to prevent these bacteria from ever colonizing in cattle, it's possible that we can have a real impact on human disease.” Notably, “[t]his could be something as simple as including some sort of antagonist in cattle feed, which would result in less shedding of the bacteria and less contamination down the road."
The findings, of course, are important because an estimated 70 percent to 80 percent of cattle herds can carry these pathogens. According to Dr. Sperandio, the finding “serves as a proof-of-principle that we might be able to target this system and help prevent food contamination."
