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E. coli Outbreak Strain May Be New, Or Just Rare

“New SuperToxic Strain,” shouts the headline from Britain’s Sky News. “Germany Wrestles with Deadly E. Coli,” reports the Los Angeles Times. “A Warning for Americans,” lectures Fox News.

Some two weeks after the onset of Germany’s E. coli outbreak, the world media have begun to take notice. Editors from Public Broadcasting and the New York Times to Bloomberg and CBS News are dispatching reporters to Germany in hopes of unraveling the mysteries of E. coli O104:H4.

Even the Wall Street Journal weighed in, having observed “economic and diplomatic disruptions” from the outbreak.

For health authorities familiar with the science of foodborne illness, all this newfound attention is good news and bad. On one hand, they hope the media attention will provide some of the information they need to answer their own questions about the German outbreak.

But the bad news, they say, is that the feverish pitch of the reporting threatens to make the European epidemic look like a bad 1950s science fiction movie, complete with a mutant monster crawling out of a dismal swamp.

Escherichia coli O104:H4, the toxic bacteria being blamed for the epidemic, appears to be a new strain of E. coli, according the World Health Organization. But epidemiologists, who make their livings monitoring these bugs, caution that more needs to be known before deciding if they have a monster on their hands.

Viewed under a microscope, E. coli O104:H4 lacks charisma — no fangs, no claws, no growls. It is indistinguishable from scores of more varieties of mostly harmless E. coli that inhabit the guts of humans and other warm-blooded animals. It is part of a vast family of bacteria that are rod-shaped — long and skinny — with one or more whip-like flagella, used as a sort of propeller, which may or not be visible even under the microscope. The same, vast family of bacteria also includes Salmonella and, for that matter, Yersinia, which causes the plague.

The numbers — O104:H4 — carry no meaning. They are merely assigned by scientists when new strains are identified. While E. coli get numbers, each strain of Salmonella gets a name — Salmonella Saintpaul or Salmonella Heidelberg — which some scientists find easier to remember.

But, despite its prosaic appearance, E. coli is a stunningly complex organism that has intrigued scientists for nearly 200 years — that is, since microscopes were available to study the bugs. Each tiny E. coli is managed by a genome composed of 5.2 million pairs of genes – genes that control every imaginable facet of the bug, for better or worse.  When that genome was sequenced, nearly 15 years ago, it was a scientific milestone.

Whatever their genetic code, E. coli thrive in the warmth of the human gut. There they perform a variety of services, such as assisting with digestion. They also reproduce at a phenomenal rate, as quickly as every 20 minutes.  When an organism reproduces that fast, it is capable of evolving far more quickly, so that a mutation can find its biological niche in weeks or months, rather than years or eons.

Some 30 years ago, health authorities investigated outbreaks of foodborne illness and traced them to E. coli O157:H7, a strain that lives in the intestines of cows, and which carries a highly poisonous Shiga toxin.  These bugs are shed in cow manure, which can contaminate milk or ground beef or vegetables growing nearby.  If consumed by humans, E. coli O157:H7 causes severe diarrhea and, in about 5 to 10 percent of cases, a potentially fatal kidney complication — hemolytic uremic syndrome, or HUS

That strain has been the cause of most serious outbreaks of E. coli poisoning, from the Jack in the Box epidemic of 1993 to the spinach and cookie dough outbreaks of recent years.

For years, scientists have debated whether E. coli O157:H7 is a newly evolved strain, or whether it has been poisoning people for centuries, without being detected by science.  That debate continues.

And now a similar discussion is likely to develop around E. coli O104:H4. 

There is ample evidence to support the idea that the German bug is new.  Scientific literature offers only one previous mention – a small outbreak in Korea in the mid-90s.  (An outbreak of E. coli O104:121 in Montana in the mid-1990s was, despite the similar coding, unrelated.) Two different research companies, in China and Germany, have quickly sequenced the genome of the outbreak strain, and both concluded that it is new.

Some health authorities cite the epidemic statistics as further evidence of a new and dangerous strain of bacteria.  The German outbreak has sickened at least 1,600 people, 500 of them with life-threatening HUS, and killed 18 — numbers that already make it one of the worst known outbreaks in recent history. In addition, the epidemic has sickened mostly adult women — an unusual pattern for E. coli outbreaks.

Those statistics may help German officials trace the epidemic to its source, (which as of Thursday still wasn’t known), explains Dr. Bill Keene, a respected foodborne illness specialist with the Oregon Health Department. But it probably says little or nothing about the nature of the bug itself — including whether it is a new strain, Keene adds.  “It’s not biologically significant,” he says.

And, while the number of potentially fatal HUS cases appears to be three or four times higher than usual, that depends on an accurate count of the overall number of illnesses, Keene explains. It’s quite possible that far more people have been sickened in Germany, but that only a small proportion have been reported to health authorities.

Either way, he and other health authorities across the US and around the world are monitoring events as they unfold in Germany, wondering if they will soon be dealing with yet another microscopic monster.

© Food Safety News
  • jmunsell

    The third-to-the-last paragraph above states: “Those statistics may help German officials trace the epidemic to its source…” End quote.
    When public health officials truly desire to prevent future recurrences of pathogenic outbreaks, such officials proactively attempt tracebacks to the source, and then to take actions to prevent future duplications of contamination entering the food supply chain. This should be basic protocol, as in Public Health 101. Unfortunately, USDA/FSIS disagrees.
    Although armed with dozens of historical events in which agency lab sampling has detected E.coli O157:H7 in meat samples, FSIS does NOT attempt tracebacks to the SOURCE slaughter plant as a result of adverse lab test results. However, when an outbreak occurs, only then does FSIS perform a traceback to the source slaughter entity. When an outbreak occurs, the news media carries the story. In such cases, the agency cannot hide the ugly details, and is forced to initiate traceback procedures. When an agency lab sample is positive for E.coli, no one knows but the agency and the affected meat plant; in the absence of public knowledge, FSIS blithely ignores the presence of E.coli, and refuses to perform a traceback to the source slaughter plant.
    Thus, FSIS intentionally ignores dozens of golden opportunities to (1) determine the true source of contamination, and (2) circumvents the opportunity to require meaningful corrective actions at the SOURCE.
    We should not be the least surprised at the plethora of ongoing outbreaks and recurring recalls in the US.
    Perhaps the aggressiveness of European health officials in this most recent outbreak will convince FSIS of the need to trace back ALL contaminated meat to the source, and more importantly, to then force the source plants to implement meaningful corrective actions.
    Don’t hold your breath.
    John Munsell

  • John Munsell

    The third-to-the-last paragraph above states: “Those statistics may help German officials trace the epidemic to its source…” End quote.
    When public health officials truly desire to prevent future recurrences of pathogenic outbreaks, such officials proactively attempt tracebacks to the source, and then to take actions to prevent future duplications of contamination entering the food supply chain. This should be basic protocol, as in Public Health 101. Unfortunately, USDA/FSIS disagrees.
    Although armed with dozens of historical events in which agency lab sampling has detected E.coli O157:H7 in meat samples, FSIS does NOT attempt tracebacks to the SOURCE slaughter plant as a result of adverse lab test results. However, when an outbreak occurs, only then does FSIS perform a traceback to the source slaughter entity. When an outbreak occurs, the news media carries the story. In such cases, the agency cannot hide the ugly details, and is forced to initiate traceback procedures. When an agency lab sample is positive for E.coli, no one knows but the agency and the affected meat plant; in the absence of public knowledge, FSIS blithely ignores the presence of E.coli, and refuses to perform a traceback to the source slaughter plant.
    Thus, FSIS intentionally ignores dozens of golden opportunities to (1) determine the true source of contamination, and (2) circumvents the opportunity to require meaningful corrective actions at the SOURCE.
    We should not be the least surprised at the plethora of ongoing outbreaks and recurring recalls in the US.
    Perhaps the aggressiveness of European health officials in this most recent outbreak will convince FSIS of the need to trace back ALL contaminated meat to the source, and more importantly, to then force the source plants to implement meaningful corrective actions.
    Don’t hold your breath.
    John Munsell