USDA researchers develop nee methods for detecting listeria
USDA scientists develop a new method to detect L. monocytogenes infection; it is a good thing, too, as the disease kills about 500 people and disables 2,500 every year in the U.S. alone
Scientists at the Wyndmoor, Pennsylvania-based Agricultural Research Service (ARS), the chief scientific research agency of the U.S. Department of Agriculture (USDA), are busy working on improving methods to detect food-borne pathogens such as the potentially deadly Listeria monocytogenes. Quick, accurate, cost-effective methods for detecting pathogenic bacteria are essential to ensuring a safe food supply.
Listeriosis, the illness caused by L. monocytogenes infection, affects around 2,500 people in the United States every year, and kills about 500. Newborns, seniors, pregnant women, and individuals with compromised or weakened immune systems are particularly susceptible. Most methods for detecting harmful food-borne bacteria rely on antibodies, which are proteins used by the immune system to fight infections and foreign bodies. Because these antibodies target very specific infections, researchers can use them to identify and locate specific pathogens. Antibodies vary in their degree of specificity. Current antibody-based methods for detecting L. monocytogenes cannot distinguish this bacterium from the mixture of harmless bacteria found in most foods, according to Shu-I Tu, a leading researcher at ARS. A molecular method called “phage display” uses bacteria and bacterial viruses, or phages, to quickly select antibodies to detect pathogens.
Now ARS scientists have employed phage display to isolate an antibody fragment that binds specifically to L. monocytogenes. This is important, as it demonstrates that antibody phage display can be used to select antibodies for pathogen detection, even where traditional methods have proved inadequate.
-read more in Laura McGinnis’s report at USDA ARS Web site [
