Deadly E. coli Strain Unscrambled
July 27, 2012

Deadly E. coli Strain Unscrambled

Connie K. Ho for — Your Universe Online

“The emergence of novel pathogens poses a major public health threat causing widespread epidemics in susceptible populations.” This is the opening theme proposed by researchers who studied a deadly form of E. coli in hopes that it would prevent another public health outbreak in the future.

In particular, a group of researchers from Michigan State University revealed that they were able to decode the strain of deadly E. Coli that hit Germany in 2011 and identified a few reasons as to why the outbreak killed so many people.

The outbreak, thought to be the deadliest related to E. coli, led to 52 deaths and affected over 3,800 people. The team of investigators found that it was linked to a virulent strain that had never appeared before in an outbreak. The scientists describe their findings in the current tissue of the academic journal PLoS One.

“What made the German outbreak so different is that many victims suffering from kidney failure were adults,” explained lead researcher Shannon Manning, a MSU molecular biologist and epidemiologist, in a prepared statement. “Rather than attacking adults, other types of E. coli that produce Shiga toxins typically damage kidneys of children under 10.”

The scientists believe that there is a way to tame the bacteria, known as E. coli O104:H4. This particular strain of bacteria has similar characteristic to other deadly E. coli bacteria, however the combination is something that researchers haven´t seen before. Researchers haven´t identified the mechanism that causes the disease, but they have identified that the biofilm of the bacteria is what makes it so deadly.

“The underlying mechanism behind the apparent increase in O104:H4 virulence is not known, though several bacterial factors have been implicated,” wrote the researchers in the report.

The group looked at the bacteria´s biofilm and was able to see how the E.coli bacteria stayed connected to the cell´s surface and grew encased in a coat that´s self-productive. When the bacteria produced a biofilm, it created more toxic genes such as the Shiga toxin. Heightened production of the Shiga toxin is one of the possible reasons that so many kidneys end up damaged and so many people died during the 2011 outbreak.

Our research demonstrates that biofilm formation is critical for toxin production and kidney damage,” noted Manning in the statement. “If we can block the bacteria from forming a stable biofilm, then it is likely that we can prevent future E. coli O104:H4 infections.”

Overall, the project was a collaborative effort. The National Institutes of Health, the U.S. Department of Agriculture (USDA), and MSU AgBioResearch funded Manning´s project. The Michigan Department of Community Health also contributed to the research.

Going forward, Manning and other researchers will be looking at producing mutant strains to stop the bacteria from creating a biofilm. They believe that this will stop the disease completely, as the conditions will not be optimal for bacteria growth.

“These data enhance our understanding of the mechanism used by the E. coli O104:H4 outbreak strain to colonize the host and contribute to toxin-mediated disease,” commented the authors in the report.