Enterococcus Uses Sonar-Like Destruction Strategy

Like a little submarine in combat:
Enterococcus faecialis
© PHIL

This finding explains how some bacteria know when to produce a toxin that makes infection more severe. "Blocking or interfering with a bacterium's detection mechanism, should prevent toxin production and limit the severity of infection,” says Michael Gilmore, PhD, lead author of the study, and currently director of research at the Schepens Eye Research Institute and professor of ophthalmology at Harvard Medical School.

Gilmore and his team have spent years studying the bacterium known as Enterococcus faecalis, one of the leading causes of hospital-acquired infections, to find new ways to treat them. Scientist know that especially harmful strains of Enterococcus produce a toxin that destroys human cells and other types of bacteria. They also knew that this toxin was made only under some conditions. Until Gilmore's study, scientists were unable to explain how the Enterococcus knew when to make it.

Gilmore and his team found that this toxin is made whenever there is another cell type in the environment near the bacterium. They discovered how these bacteria know when other cells are present, and respond accordingly.

In the laboratory, the team found that Enterococcus releases two substances into the environment. One substance sticks to foreign cells. The second substance reports back and tells the Enterococcus to make the toxin. If no cells are in the area, the first substance sticks to the second, preventing it from reporting back to the Enterococcus, and as a result, no toxin is made. According to Gilmore, "These bacteria are actively probing their environment for enemies or food. Based on whether or not they ‘see' other cells, they make the toxin appropriately.”

"This discovery will help us to develop new ways to treat infections that are resistant to antibiotics, making them less severe. Based on an understanding of how this toxin system works, we hope to develop toxin inhibitors,” Gilmore sums up.

MEDICA.de; Source: Schepens Eye Research Institute