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E. coli Conference: Research Should Focus on the Source

The report from the so-called “supershedders” conference on the future of enterohaemorrhagic Escherichia coli (EHEC) research — held recently in Scotland — is out. It identifies key knowledge gaps and recommends areas for future research.

The workshop stemmed from the controversial 2005 E. coli outbreak in South Wales and was organized by the Food Standards Agency in Scotland, the Knowledge Transfer Network Biosciences and the University of Edinburgh.

The report focusing on the future of E. coli research was published by Scotland’s Food Safety Agency. The workshop’s goal was to reduce the health impact of the pathogen on humans by tacking it at the source.

Experts from around the globe attended the workshop in Midlothian, where priorities were agreed for research to help tackle EHEC at the main source of infection, the cattle gut.

Delegates shared knowledge of the factors leading to the transmission and maintenance of infection in cattle, particularly the role of ‘supershedders’ – cattle that excrete particularly high levels of E.coli O157 in their feces.

Supershedders are thought to play an important role in the spread of the bacteria to other cattle and the likelihood of transmission to humans via the environment or raw food.

There was also discussion on intervention strategies being explored in other countries to reduce EHEC shedding by cattle and the feasibility of introducing these in the UK.

The main source for EHEC is the gut of ruminant animals, particularly cattle, which excrete or shed the bacteria in their feces.

Some cattle excrete EHEC at significantly higher levels than other animals in the herd, a phenomenon known as ‘supershedding’. Humans can become infected through direct exposure to feces in the environment or when fecal contamination enters the water supply or food chain

The key recommendations in the report include:

- Improve understanding of the epidemiology of EHEC infection in cattle, humans and environmental reservoirs the need for more studies on the biology of host-bacteria interactions and the relationships between cattle, the environment and human infection rates.

- Support further research on potential intervention strategies and how effective they need to be to have an impact on human health.

- Promote international collaboration to investigate how sequence based typing schemes can be used to investigate the evolution and virulence of strains

- Improve engagement between the industry, regulators and consumers to enhance understanding of the cost/benefit of intervention strategies as well as motivators and barriers to their implementation.

The 2005 E. coli outbreak was the largest ever experienced in Wales and the second largest in the history of the United Kingdom. It was best known for the death of 5-year-old Mason Jones, and involved a total of 157 cases, mostly children from 44 schools.

Because of the controversy generated by the outbreak, Professor Hugh Pennington was enlisted to conduct a public inquiry into the tragedy. He produced a 45,000-page record, concluding the source of the contamination of a butcher serving the schools, John Tudor & Sons.

Among its recommendations, the Pennington inquiry called for exploring the feasibility of identifying “supershedder” cattle on farms “as a potential means of reducing the likelihood of spreading E.coli O157 to other cattle.”

E. coli O156:H7 is the best known among Enterohaemorrhagic E.coli (EHEC), the group that also includes the “Big Six” E. coli strains: O26, O111, O103, O121, O45 and O145.

In the United States, the U.S. Department of Agriculture does not permit O157:H7 or any of the “Big Six” in meat. If any of these strains are consumed, they can result in mild to severe symptoms including abdominal cramps, vomiting and sometimes-bloody diarrhea

EHEC infections can also lead to serious complications including hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. These conditions affect the blood, kidneys and, in severe cases, the central nervous system, and can even lead to death.

The United Kingdome experiences about 1,000 E. coli infections annually, with most being attributed to O157:H7,

Controlling the spread of E. coli is a priority for FSA.

Photo: Mason Jones, Age 5

© Food Safety News
  • Jim

    This is a problem that is inherent in the Industrialized Meat System.
    What better place for the “super shedders” to spread their virulent E coli strains to the herd than the massive feed lots where beef cattle are “finished” for slaughter crammed together in pens knee-deep in their own manure — a perfect medium for spreading E. coli O156:H7 as well as O26, O111, O103, O121, O45 and O145??
    And where, during their stay, they’re beefed up on an un-natural (for forage-feeding cows) diet of corn and distiller’s grains (ethanol waste) repeatedly shown to promote strains of virulent E coli.
    Yet another dirty little secret is where does all this toxic waste go when the pens are cleaned or the stockyards are exposed to winds and rains and flooding? And how far downwind/downstream to you or your food crops have to be before exposure to the parts per million are no longer dangerous?

  • http://canadianfoodsafetyalliance.ca/ Canadian Food Safety Alliance

    A Canadian company has developed a vaccine that eliminates the shedding of E. coli O157 thats adminstered on-farm. Visit the Canadian Food Safety Alliance website to show your support.

  • Chuck

    Jim, where do you get your nonsense? It’s plain that you’ve never been near a feed yard but you still want to spread innuendo. Get the facts straight, first, and then you can speak.

  • Jim

    Chuck — been there, actually — but If you’ve got something different to say I’d love to hear it……

  • http://www.johnmunsell.com John Munsell

    The third paragraph above is erudite, and quickly reveals why America has been artificially thwarted in its attempt to rein in the plethora of E.coli outbreaks. The sentence states “The workshop’s goal was to reduce the health impact of the pathogen on humans by tacking (sic) it at the source”. AT THE SOURCE is imperative, but has not been a USDA/FSIS priority until recent years. For example, on October 8, 2010, FSIS issued Notice 58-10 which requires inspectors to document the SOURCE of being being sampled for lab analysis. Prior to this Notice, inspectors collecting samples were only to document the location of the grinder producing the burger being sampled. So, if your local meat market (which does not slaughter) had its ground beef sampled by FSIS, and the sample detects the presence of E.coli 157:H7, FSIS has historically placed all blame upon the small local shop which purchases all its meat from source slaughter providers. Pretty nifty, eh? Yes, if you are the originating slaughter plant which unwittingly contaminated beef carcasses with invisible enteric bacteria.
    Fortunately, the top two FSIS officials (Dr. Elisabeth Hagen and Al Almanza) have repeatedly stated their support of prevention at the source, and are implementing Traceback protocol. Unfortunately, it’s also true to state that (1) Prevention at the SOURCE & (2) Tracebacks to the SOURCE should have been a foundational building block upon which meat inspection policies were designed. History has repeatedly proven that FSIS had traditionally ignored both (1 & (2), to their discredit. Only time will tell if institutionalized FSIS and industry opposition to (1) & (2) will be sabotaged, perhaps even declared illegal. I’m not optimistic.
    On October 2 & 3, Chicago will host an E.coli conference, for which many high-powered speakers from the industry, academia & FSIS will make presentations. It will be most interesting to witness if American officials have the same focus on the SOURCE as shown by Scotland. Dan Flynn should attend.
    John Munsell