New Research Paves Way For E. Coli Vaccine

By C. Rajan, contributing writer

An international team of researchers have found that various strains of the E.coli bacteria from around the world have several key similarities that can be exploited for preparing a global vaccine to fight this often fatal infection.

Escherichia coli (E. coli) is a family of bacteria found in the digestive system of humans and many animals. While many strains of E.coli are harmless, certain strains of E.coli produce a toxin that causes severe diarrhea, stomach cramps, nausea, and vomiting. In severe infections, patients develop complications such as kidney failure, anemia, and bleeding.

E. coli is responsible for approximately 400 thousand deaths every year and 400 million cases of diarrhea annually in many countries around the world.

This largest-of-its-kind study of the bacterium enterotoxigenic Escherichia coli (ETEC) analyzed whole-genome sequence data for 362 different ETEC strains from 20 countries over the past 30 years. The researchers compared the way the bacterium strains attach to human stomach lining — an indication of the bacteria’s colonization factor — and found that the strains unexpectedly clustered into very closely related groups.

While ETEC strains were believed to be very different across the world, this study traced the 21 main strains back to their origin to an individual bacterium that was able to infect humans and spread, due to global travel.

This data indicated that the E. coli bacterium is similar across Asia, Africa, and the Americas, suggesting that a vaccine could be developed that would be effective worldwide. Moreover, E.coli samples taken from both children and adults were also similar, so the potential vaccine could work across different patient groups, as well.

"This research strengthens our belief that it is possible to target a broad range of ETEC groups with one vaccine," says Professor Gordon Dougan, senior author from the Wellcome Trust Sanger Institute. "By targeting the most prevalent colonization factors in these lineages, we stand a chance of developing a vaccine that will reduce the disease burden caused by this bacterium. This work is now underway at the Sanger Institute."

Researchers from the Wellcome Trust Sanger Institute, Cardiff University, and University of Gothenburg participated in this collaborative research effort.

The researchers claim that the whole-genome sequence dataset from this study will help scientists identify proteins that may be important for virulence and help them locate the shared weaknesses in ETEC bacteria that could be exploited for vaccine development.

The study was published in the journal Nature Genetics.