Mike the Mad Biologist

Consider this a post wherein I engage in some speculation, and hope that I’m very, very wrong. You see, the ‘German’ E. coli O104:H4 outbreak (‘HUSEC041′) has taken a confusing turn:

The strain of E. coli blamed for 46 deaths in Germany appears to have resurfaced in France, the French Ministry of Health said.

The new outbreak has sickened eight people, who went to two hospitals in Bordeaux, authorities said.

Officials interviewed seven of them, all of whom reported having attended an open house at a children’s recreation center. Six of them reported having eaten sprouts during the visit, “particularly used in decoration of a gazpacho,” the health ministry said.

Two of the eight patients have hemolytic uremic syndrome. The strain of E. coli isolated from one of them “has the same characteristics as the strain responsible for a large epidemic” of enterohemorrhagic E. coli in Germany over the past several weeks, which has been blamed on sprouts, the ministry said in a statement.

The seeds for the sprouts consumed at the recreation center were planted and grown in France, officials said.

An investigation found the seeds were supplied by a British company, but no definitive link has been established, an official with France’s economy ministry said.

Meanwhile, the UK has issued a warning about eating sprouts, including “alfalfa, mung beans (usually known as beansprouts) and fenugreek.” Not sure what fenugreek is, but you shouldn’t be eating it (them?).

One of the downsides of this early post about the misidentification of the outbreak strain is that it has made me into something resembling an authoritative source (fools). So I’ve tried to stay away from any speculation, since speculation has a way of working through the intertoobz and coming out the other end as a definitive statement. But this latest development leads to me speculate. And speculate the Mad Biologist will.

Simply put, I don’t think this is a single point source outbreak: a contaminant enters a single processing facility or farm and spreads through the food chain. In fact, I have never thought this is a single point source outbreak.

Before we had news of this latest outbreak, there were reports of finding HUSEC041 in streams outside of Frankfurt, Germany. I find it unlikely that this cames from a sick person, went through the sewage system, and happened to be the E. coli isolated–most E. coli from any sewage system won’t be this outbreak strain (otherwise, there would many thousands of people in Frankfurt–Frankfurters?–with bloody diarrhea and hemolytic uremic syndrome). Unlike E. coli O157:H7, which through some evolutionary flukes has a couple of biochemical changes that allow selective isolation (i.e., you have specifically hunt for it), HUSEC041 looks just like ‘normal’ E. coli*. If you’re observing it in a stream sample, that seems too abundant relative to other E. coli to be a sewage contaminant.

What I think is happening is that HUSEC041 has, for whatever reason, skyrocketed in its reservoir (where it lives outside of people). This has led to separate, multiple introductions into the food supply. While enteroaggregative E. coli (‘EAEC‘) like HUSEC041 aren’t supposed to live in non-human animals (children and infants are thought to be the reservoir), EAEC isn’t supposed to produce Shiga-like toxin either, so there’s a first time for everything. (Of course, no one has been screening asymptomatic H. sapiens for HUSEC041).

I really hope I’m wrong, since if I am, that would mean there was a single point of introduction which will ultimately burn itself out. If I’m not, well, then we have a new strain of shigatoxinogenic E. coli (STEC) to worry about….

*Since HUSEC041 is resistant to multiple antibiotics, I suppose one could select antibiotic resistant isolates. I have no idea if the authorities are doing that.

Comments

  1. #1 BenK
    June 27, 2011

    Fenugreek is an herb. I use it dried in stew and in curry. Apparently, people eat it fresh as well.

    I wonder if we are seeing an E. coli that is adapted to carriage on plants. Only time will tell.

  2. #2 Hercules Grytpype-Thynne
    June 27, 2011

    people in Frankfurt–Frankfurters?

    Jawohl.

  3. #3 Helane Shields
    June 28, 2011

    Enteroinvasive E. coli (EIEC) and Enteroaggregative E. coli (EAEC) are found ONLY in HUMANS – not animals. (Wikipedia)

    German scientists have concluded the source of the e. coli outbreak is human, not cattle. Surface waters receiving treated sewage effluent may be an exposure risk. Treated human sewage sludge biosolids spread on cropland may also be a transmission risk:

    “According to the head of the national E. coli lab at the German Federal Institute for Risk Assessment, the strain responsible for the outbreak has been circulating in Germany for 10 years, and in humans not cattle.[47] He said it is likely to have got into food via human feces. ” (Wikipedia E. coli outbreak)

    “Germany confirms human E. coli transmission ”
    “Officials on Friday said that the strain had been found in a stream in Frankfurt.

    Test samples were being taken from a nearby sewage treatment plant to try to detect a possible source of the contamination.

    Authorities say E. coli had been detected before in the 30km stream. ”
    http://english.aljazeera.net/news/europe/2011/06/201161941630620984.html

    “Influence of soil type, moisture content and biosolids application on the fate of Escherichia coli in agricultural soil under controlled laboratory conditions.

    “To determine the fate of the enteric indicator organism, Escherichia coli, in sewage sludge (biosolids)-amended agricultural soil in relation to soil type and moisture status under controlled conditions.

    “E. coli numbers increased in soil following addition of dewatered, mesophilic anaerobically digested sludge
    (Smith SR Lang NL 2007)

    “After addition of fresh biosolids to fresh soils, the E. coli MPN rose immediately (Fig. ā€‹(Fig.1),1), from just under 102 MPN gāˆ’1 dry matter to about 106 MPN gāˆ’1 dry matter over the ensuing 4 days, reaching values significantly greater (day 4, P of <0.01 for all four soil layers) than those obtained with the treatments where fresh biosolids were added to sterile soils (between 102 and 103 MPN gāˆ’1 dry matter)"

    (Susan Springthorpe, et al 2006)

    Public health and food safety are at risk by the presence of virulent, antibiotic resistant human e coli in sewage sludge biosolids which are land applied to crops and agricultural fields in the United States and Europe.

    Helane Shields, Alton, NH hshields@tds.net

  4. #4 Caroline Snyder
    June 28, 2011

    The e.coli strain responsible for the German outbreak is not new. It is not found in the guts and manure of ruminants,
    but in the human gut and in human feces. Northeast Germany and the US permit human waste ( sludge) to be spread on food and feed crops. Other disease causing e.coli strains survive and sometimes re-grow in sludged soil. So maybe it is time to phase out the practice of using human waste as fertilizer.

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