NEW YORK, June 8 – The fruits of the first collaboration between the US Department of Agriculture’s Agriculture Research Service and The Institute for Genomic Research has yielded the sequencing of the pathogen Listeria monocytogenes , the organizations announced this week.
The USDA ARS provided the Listeria sample to TIGR in November, according to John Luchansky, research leader of the ARS Microbial Food Safety Research Unit. The isolated DNA supplied to TIGR was of the Listeria monocytogenes serotype 4b strain, which is the type responsible for most food-borne listeriosis outbreaks, according to the ARS.
With the completion of the initial sequencing, approximately 98 percent of the bacterial DNA sequencing is complete, said Luchansky. The next steps will include closure of existing gaps and then annotation.
By studying the bacterium’s genome, the ARS hopes to find out what makes the strain pathogenic once it is consumed by humans and how it survives prior to ingestion, said Luchansky, who pointed out that the strain lives in many conditions inhospitable to other bacteria, including a 25 percent salt solution, refrigeration and low pH.
Every year there are about 2,500 food-borne cases of listeriosis and approximately 500 deaths in the US, according to the ARS. Luchansky pointed out that in addition to the health costs, there is an economic burden to industry because of food recalls from Listeria contamination.
James Lindsay, national program leader for food safety at the USDA ARS, said that the collaboration with TIGR was considered a success, and that the organizations were “in the process of negotiation to sequence another pathogen.” Lindsay would not reveal the identity of the pathogen.