New strategy can prevent onset of E. coli related illness

The recent outbreak of E. coli infection in Germany has put a potentially fatal bacterium back on everyone's radar screen. While some researchers are looking for a better way to treat the disease, professor Debora Foster of the Department of Chemistry and Biology at Ryerson University is taking a different approach. Foster and her research team are exploring how to prevent the onset of E. coli related illness.

Their recent discovery that a novel peptide, or small protein, is effective against several strains of the bacteria looks promising. It was covered in an article on new research approaches to combating E. coli in the July 2011 issue of Nature Medicine, a leading international journal for biomedical research.

In collaboration with researchers from the University of Southern California and San Diego State University, Foster is investigating an antimicrobial agent that could be used to develop a spray for fruits and vegetables that are potentially contaminated with Shiga toxin-producing E. coli, the same one that has caused the recent outbreak in Germany. This bacterium infects the human large intestine, causing hemorrhagic colitis and occasionally leading to more serious and even life threatening illnesses such as hemolytic uremic syndrome.

"We're investigating an antimicrobial peptide that interferes with the DNA repair mechanisms that enable the E. coli bacterium to survive exposure to human gastric acid," Foster explained. "One of our natural defence mechanisms is the killing action of stomach acid. Our strategy is to develop a preventative antimicrobial agent that enhances the killing action.

"We are very excited by our initial findings. We will continue testing to develop a deeper understanding of the peptide's effectiveness" she said.

This project grew out of discussions between Foster and her collaborators, Dr. Anca Segall from San Diego State University and Dr. Steve Goodman from the University of Southern California about the possibility that this novel peptide may be able to jeopardize the survival of this serious pathogen through the stomach. Foster and her research group decided to investigate.

"I was amazed by our findings that even a brief five-minute treatment with this peptide profoundly impaired the ability of several different strains of E. coli associated with severe human disease to survive exposure to acid similar to that found in the human stomach."