Health Law

New Research on How Listeria Enters Human Bloodstream

By David Babcock

Researchers at Purdue and Michigan are reporting on a new study into how listeria is able to enter the human bloodstream.  Listeria monocytogenes  has been in the news lately following an outbreak, with multiple fatalities, linked by Texas health officials to celery.   In addition, there have been recent recalls  and product seizures linked to cheese, and two different pork products in  Ohio and California. 

Arun Bhunia, Purdue professor of food science and Kristin Burkholder, from the University of Michigan, report that "Pathogenic listeria tricks intestinal cells into helping it pass through those cells to make people ill, and, if that doesn't work, the bacteria simply goes around the cells."

Their research indicates that listeria:

even in low doses, somehow triggers intestinal cells to express a new protein, heat shock protein 60, that acts as a receptor for listeria. This may allow the bacteria to enter the cells in the intestinal wall and exit into a person's bloodstream.

Bhunia and Burkholder's findings were published in the early online version of the journal Infection and Immunity.

Ingestion of the listeria bacteria can cause listeriosis,a serious infection that can cause fever, muscle aches, nausea and diarrhea, as well as headaches, stiff neck, confusion, loss of balance and convulsions if it spreads to the nervous system. According to the U.S. Centers for Disease Control and Prevention, it sickens about 2,500 and kills 500 people each year in the United States and primarily affects pregnant women, newborns, older adults and those with weakened immune systems.

One of the reasons that listeria poses a threat is that the infective dose is very low. "Even 100 to 1,000 listeria cells can cause infection," Bhunia said. "We believe that these mechanisms are what allow listeria to cause infections at such low levels."

Full post as published by Food Poison Blog on October 28, 2010 (boomark / email).