Immunomagnetic Beads Can Attract Plague Bacteria
By Laura McGinnis
May 22, 2009
Agricultural Research Service (ARS) scientists have used antibody-coated immunomagnetic beads (IMBs) to detect Yersinia pestis, the bacterium that causes bubonic plague.
While similar techniques are often used to detect various bacterial species, the methods must be altered to suit specific pathogens. This is done by taking advantage of variations in the biological makeup of the different bacteria. Because antibodies can be selected that bind to very specific targets, antibody-coated IMBs can be used to specifically remove target pathogens from the other harmless bacteria present in most food.
The trick to IMB technology is finding an antibody that attaches to one, and only one, target--for example, a Y. pestis antigen. At the ARS Eastern Regional Research Center in Wyndmoor, Pa., microbiologist George Paoli and his colleagues have developed IMBs to capture Y. pestis. In preliminary tests with milk samples, the technology has been successful.
The team is also using genetic methods that rely on a common DNA test known as the "polymerase chain reaction," or PCR. The group has developed PCR-based methods to detect Y. pestis and differentiate it from other foodborne bacteria, including two closely related Yersinia species, Y. enterocolitica and Y. pseudotuberculosis.
They have also developed a PCR method that targets genes related to the virulence of Y. pestis. This test could be used to determine the virulence of a particular strain of the pathogen and estimate its potential public health impact.
The scientists are currently working to combine the different areas of this research to develop a complete set of tools for the detection of Y. pestis in food, as part of a holistic approach to food security.
Research efforts like these ensure that U.S. consumers and food industry professionals have the most advanced technology and information available to protect them from potential pathogen threats.
Read more about this research in the May/June 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.