German researchers suspect cucumbers from Spain were the cause of a massive enterohemorrhagic Escherichia coli (EHEC) outbreak which hit the northern regions of the country. According to the Robert Koch Institute (RKI), so far 214 patients developed hemolytic uremic syndrome (HUS), a potentially fatal complication of EHEC infection, characterized by destruction of red blood cells and severe kidney problems. At least two patients died.
Local authorities in Hamburg today announced that they had isolated the bacteria EHEC four cucumbers. Three of the samples came from a big market in Hamburg selling shops as well as restaurants and caterers of fruits and vegetables. These cucumbers from two organic producers in Spain. Scientists have speculated in recent days that manure from infected animals used on an organic farm could have spread the bacteria to vegetables. A fourth sample was from a restaurant, and it was not immediately clear where the cucumber was grown. After the announcement, the stores have started taking Spanish cucumbers on the shelves.
Consumers were already hesitant about vegetables since scientists at RKI and the Federal Risk Assessment Institute announced the results of a first case-control study Wednesday: Women who had become EHEC infection were significantly more likely to have eaten raw tomatoes, cucumbers and lettuce in the days before falling ill than women who were not sick.
The scientists used a detailed questionnaire to ask 25 women EHEC patients and 96 women living in the same areas of what they had eaten in the days before hatching. Only women were included in the study because they got sick more often than men in the home. "It also strengthened the results of the study, because it meant that we could ignore all the sex-specific differences in eating habits," says Gérard Krause, head of the department of infectious disease epidemiology at RKI.
statistical analysis revealed that 92% of women who had been infected already had eaten tomatoes. only about 60% of healthy women did. "for something that people eat so often, it is a big difference "said RKI expert Klaus Stark. The results for cucumbers and lettuce were similar, but slightly smaller. These three results are statistically significant. Experts invited Germans, especially in the north, not to eat it raw tomatoes, cucumbers, lettuce or until further notice.
This advice remains in place. "It is certainly possible that more than one of these foods is responsible," said Reinhard Burger, president of RKI. Scientists also want to be sure that the results of Hamburg are confirmed in another laboratory.
New idea of the nature of the bacteria could help. scientists of the National reference Laboratory on hemolytic uremic syndrome in Münster have samples of all 42 cases of EHEC that occurred among patients HUS in Germany since 1996. They . have identified the strain of the current epidemic as HUSEC41, the type of sequence ST678 in common serotype classification which means the pathogen is a E. coli O104: H4
according to Helge Karch, head of the laboratory of Münster, O104: H4 has not a single documented outbreak in his name "that's why we were very surprised that this strain can cause severe illness in a short time," he said. -he.
Karch and others are now working on sequencing the entire genome of HUSEC41 and establish a new and easy way to diagnose this particular strain of EHEC. This is important because the bacterium is difficult to distinguish from normal, non-pathogenic E. coli .
The strain is also eae-negative, which is unusual for a pathogen E. coli . The gene eae encodes intimin protein that bacteria use to attach to the intestinal wall. "This has been shown to be particularly important to infect children, so it could be an explanation, why we mostly see adult patients in this epidemic," said RKI expert Stark.
Meanwhile the epidemic continues in full force. "he looked a little, as there was a dip in the numbers, but in particular in Hamburg many patients are still present in the hospital with bloody diarrhea" said Stark. the next few days will show whether the warning about eating cucumbers, tomatoes and lettuce had an impact on the epidemic.
* This article has been corrected . June 3 An earlier version of this story incorrectly reported that researchers had isolated the strain EHEC O104 H4 :. cucumbers
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