Scientists working with the Agriculture Research Service have discovered key gene and chemical interactions that allow E. coli O157:H7 bacteria to colonize the gut of cattle. They says the bacteria senses a key chemical that plays a critical role in allowing the bacteria to colonize inside the cattle's gastrointestinal tract. This is an important finding because cattle not only host, but can shed the deadly human pathogen.
ARS animal scientist Thomas Edrington explains: To proliferate, E. coli express genes differently based on their environment, such as outside the cattle host, inside the cattle rumen, or even at the end of the cattle GI tract. Having a better understanding of when, why and how these bacteria colonize could lead to practical applications in the future.
Research shows that "quorum sensing" chemicals called acyl-homoserine lactones, which are produced by other bacteria, are present within the bovine rumen but absent in other areas of the cattle GI tract. AHLs are important because E. coli harbor a regulator, called SdiA, which senses these AHLs and then prompts the E. coli to attach and colonize.
The researchers believe that limiting production of the SdiA chemical, or blocking bacterial reception of the AHLs, may eventually lead to new strategies for keeping E. coli from attaching inside the animal.