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E. coli colonization trigger identified

Microbiologists identify and deactivate trigger to EHEC colonization in grain-fed cattle.
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May 22, 2010
By dvm360.com staff
Dallas -- Microbiologists at the University of Texas (UT) Southwestern Medical Center, working with the U.S. Department of Agriculture, have discovered at least two ways to prevent outbreaks of food-borne illnesses caused by the Escherichia coli strain enterohemorrhagic 0157:H7, or EHEC, in grain-fed cattle.

By either eliminating or mutating the protein SdiA found in EHEC, researchers were able to stop the bacteria from reaching its colonization site -- the cow's recto-anal junction. As 70 percent to 80 percent of cattle herds in the United States carry EHEC, and EHEC is responsible for outbreaks worldwide resulting in diarrhea to death, these findings are encouraging, according to researchers.

Dr. Vanessa Sperandio, associate professor of microbiology and biochemistry at UT Southwestern Medical Center and senior author of the study, which will be available in an upcoming issue of Proceedings of the National Academy of Sciences, says the next step is to assess what happens in grass-fed, rather than grain-fed, cattle.