• Listeria Tough to Fight Because Of Adaptability
  • September 10, 2014 | Author: Seth A. Katz
  • Law Firm: Burg Simpson Eldredge Hersh & Jardine, P.C. - Englewood Office
  • Listeria is a bacterium that can be found in food that can cause people to get sick.. Due to its ability to adapt to its environment, Listeria is tough to kill, according to researchers from the Department of Biochemistry and Molecular Biology at the University of Southern Denmark.

    Associate Professor Birgitte Kallipolitis and her colleagues studied how Listeria reacts when exposed to a number of substances which usually fight pathogenic bacteria. The study revealed Listeria began producing special RNA molecules to combat the antibiotics, bile, salt, acid and ethanol.

    Listeria is constantly adapting to its surroundings and takes on a number of strategies to withstand threats, Kalliplitis said. In addition, she noted Listeria is also effective in not attracting unwanted attention in the human body.

    "On the one hand, Listeria needs to produce some special proteins that enable it to infect the cells in our body," Kallipolitis said. "On the other hand, it must ensure that the body's immune system does not detect these proteins. It is vital for Listeria to keep a balance between producing enough of these proteins but not so many that they are detected by the immune system - and it masters just that."

    "With these RNA molecules the bacteria can adjust how much or how little to produce of various proteins," Kallipolitis added. "For example it can downgrade the production of the protein LapB, which it uses to enter our cells. If this production is not downgraded, the bacterium will potentially be detected and fought by the immune system."

    In fact, researchers only saw the production of the RNA molecules when they exposed Listeria to the threatening substances in the lab.

    "When there are no threats, Listeria does not produce them. This reveals part of the mechanism behind Listeria´s extreme adaptability," Kallipolitis said.

    Kirkland recalls pesto after Listeria contamination
    Washington-based food manufacturer Kirkland recently announced a voluntary recall of about 20 containers of basil pas pesto packed in eight ounce tubs over fears it might have been contaminated with Listeria. The problem was discovered by the Washington State Department of Agriculture. 

    The pesto was sold from Aug. 18 to Aug. 21 to a number of convenience stores, cafes and espresso stands in King and Snohomish counties, Washington.

    Production of the pesto has been suspended until agriculture officials can investigate the source of the problem.