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# New Vaccines May Help Thwart E. coliO157:H7
- URL: https://www.foodconsumer.org/vaccines_may_thwart_e_coli_o_157h7_0704100605/
- Published: 2010-04-07T06:04:00.000Z
- Updated: 2026-09-15T12:46:17.000Z
- Description: Agricultural Research Service microbiologists developed two experimental vaccines built from E. coli O157:H7 strains missing the hha gene, or hha plus sepB. In preliminary tests, immunized Holstein calves shed reduced amounts of the bacteria after being dosed with it.
- Author: Food Consumer
- Tags: Sci-Tech, #vivvo-import

By Marcia Wood

Immunizing calves with either of two forms of a vaccine newly developed by [Agricultural Research Service](http://www.ars.usda.gov/?ref=foodconsumer.org) (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.

In humans, however, *E. coli* can cause bouts of diarrhea and, sometimes, life-threatening hemolytic uremic syndrome.

Research microbiologists [Vijay K. Sharma](http://www.ars.usda.gov/pandp/people/people.htm?personid=44894&ref=foodconsumer.org) and[Thomas A. Casey](http://www.ars.usda.gov/pandp/people/people.htm?personid=44880&ref=foodconsumer.org) developed the novel vaccines in their laboratories at the agency's [National Animal Disease Center](http://www.ars.usda.gov/main/site%5Fmain.htm?modecode=36-25-30-00&ref=foodconsumer.org) in Ames, Iowa and are seeking a patent for it.

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.

In preliminary tests, Holstein calves were immunized at age 3 months with a placebo or either form of the vaccine. Six weeks later, the animals were given a dose of *E. coli* O157:H7, and, for the next 18 days, their manure was tested for evidence of the microbe. Calves that received either vaccine had reduced or non-detectable levels of *E. coli* in their manure within only a few days after being inoculated with the bacteria, Sharma and Casey found.

Some of the scientists' earliest work with the *hha* gene is documented in the journal[*FEMS Microbiology Letters*](http://www.fems-microbiology.org/website/NL/page21.asp?ref=foodconsumer.org).

ARS is the principal intramural scientific research agency of the [U.S. Department of Agriculture](http://www.usda.gov/?ref=foodconsumer.org). The *E. coli* investigations help ensure food safety, a USDA top priority.

Originally published on ARS.USDA.gov on December 17, 2009