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"By Marcia Wood
December 17, 2009
Immunizing calves with either of two forms of a vaccine newly developed by Agricultural Research Service (ARS) scientists might reduce the spread of sometimes deadly Escherichia coli O157:H7 bacteria. The microbe can flourish in the animals' digestive tracts, yet doesn't cause them to show clinical symptoms of illness.
Preventing E. coli O157:H7 from proliferating inside cattle helps limit contamination of meat at the packinghouse, and reduces shedding of the microbe into the animals' manure. Manure-borne E. coli can be moved by rainfall into drinking water. What's more, it can end up in irrigation water, and can contaminate fruits, vegetables or other crops, increasing risk of an outbreak of foodborne illness.
One form of the vaccine is comprised of cells of a strain of E. coli O157:H7 that is lacking a gene known as hha. A second form of the vaccine contains an E. coli strain lacking both hha and a second gene, sepB. In either vaccine, the E. coli strain produces a large quantity of what are known as immunogenic proteins. These proteins trigger the immune system response that prevents E. coli O157:H7 from successfully colonizing cattle intestines.
Some of the scientists' earliest work with the hha gene is documented in the journal FEMS Microbiology Letters."
December 17, 2009
Immunizing calves with either of two forms of a vaccine newly developed by Agricultural Research Service (ARS) scientists might reduce the spread of sometimes deadly Escherichia coli O157:H7 bacteria. The microbe can flourish in the animals' digestive tracts, yet doesn't cause them to show clinical symptoms of illness.
Preventing E. coli O157:H7 from proliferating inside cattle helps limit contamination of meat at the packinghouse, and reduces shedding of the microbe into the animals' manure. Manure-borne E. coli can be moved by rainfall into drinking water. What's more, it can end up in irrigation water, and can contaminate fruits, vegetables or other crops, increasing risk of an outbreak of foodborne illness.
One form of the vaccine is comprised of cells of a strain of E. coli O157:H7 that is lacking a gene known as hha. A second form of the vaccine contains an E. coli strain lacking both hha and a second gene, sepB. In either vaccine, the E. coli strain produces a large quantity of what are known as immunogenic proteins. These proteins trigger the immune system response that prevents E. coli O157:H7 from successfully colonizing cattle intestines.
Some of the scientists' earliest work with the hha gene is documented in the journal FEMS Microbiology Letters."
