USDA Research Agency and TIGR Sequence Genome of Food Borne Pathogen
June 7, 2001
WASHINGTON, June 7, 2001 â€”Â Secretary of Agriculture Ann Veneman announced today that a major milestone has been reached with the sequencing of the genome of a highly virulent strain of a food-borne pathogen, Listeria.
The project is a collaboration between the Agricultural Research Service (ARS), USDA's chief scientific research agency and The Institute for Genomic Research (TIGR), a not-for-profit research institute responsible for random sequencing, closure and annotation of the Listeria genome.
Under the direction of Karen E. Nelson, Ph.D. and Claire M. Fraser, Ph.D., president and director of TIGR, researchers began to sequence the genome of a Listeria monocytogenes serotype 4b strain in January 2001. A serotype 4b strain was selected because most food-borne listeriosis outbreaks, and 50 percent of sporadic cases, are caused by strains of this serotype.
"Listeriosis is a significant public health problem, and people are entitled to the safest food they can have," Veneman said. "We have now taken a major step toward having the information that will be the basis for developing better methods to ensure the safety of our food." Listeria is widespread in the environment and is associated with some ready-to-eat food products such as hot dogs, lunchmeats, smoked fish, and certain types of soft cheeses. Each year, there are about 2,500 food-borne cases of Listeriosis and about 500 deaths.
"Sequencing the Listeria genome will help us better understand how this bacterium persists in foods and in food processing plants, and this will help us reduce the incidence of contamination and food-borne illness," said ARS Administrator Floyd Horn.
"With the genome sequenced, we will be better able to study this bacterium at the most fundamental level," explained John B. Luchansky, research leader of ARS's Microbial Food Safety Unit, Eastern Regional Research Center in Wyndmoor, PA, who oversees the project for ARS.
"We can use this information to study the viability and the virulence of the bacterium on the farm, in food processing plants and in food. This in turn will allow us to develop strategies to control the bacterium at various points along the food chain," he said. What has been finished is the "random phase," in which individual pieces of DNA have been sequenced. The next step is to assemble the sequenced DNA fragments into a complete genomic map.
"Once we complete this, we plan to sequence portions of other Listeria strains and species so we can compare them and identify genes that impact on their persistence in animals and foods, and on their pathogenicity in people," Luchansky said. "We are also interested in studying gene expression and protein function."
Scientists will be able to access the genetic sequence information through the TIGR website at http://www.tigr.org/tdb/ after June 8.