June 13, 2011
Tracking The Origins Of Germany’s E. Coli Outbreak
German authorities on Sunday said they have not been able to resolve the deadly E. coli strain that has so far been the cause of 34 deaths in the country, and the government fears more people could die.
Officials determined Friday that sprouts grown at the farm in Lower Saxony state, in northern Germany, were to blame for the aggressive outbreak, which has already sickened nearly 3,300 people.
But the state's agriculture ministry said it wasn't clear whether the E. coli was carried in from workers, or if the bacteria got onto the farm on seeds or by other means.
The total number of deaths linked to the outbreak has reached 35, all in Germany, except for one in Sweden, according to the World Health Organization (WHO).
"More fatalities cannot be ruled out, painful though it is to say," Health Minister Daniel Bahr told the Bild am Sonntag newspaper, while adding that the number of new cases was in decline.
"The continuing fall in the number of new infections gives grounds for optimism. But that does not rule out more cases of EHEC (enterohaemorrhagic E. coli)," he said.
Scientists are working feverishly to dissect the bacteria's DNA to find clues about how to treat people and hopefully prevent future outbreaks. So far, one strain from a German patient has been sequenced by German and Chinese scientists.
Experts are saying there are few hints about why this particular E. coli strain might be so deadly.
The bacteria causing Europe's widespread outbreak is likely the product of another strain first discovered 10 years ago in Germany, but with dangerous mutations, according to the experts. The outbreak has been blamed for several hundred incidents of people who have developed life-threatening kidney failure.
Flemming Scheutz, head of the World Health Organization's Collaborating Center laboratory in Denmark, said the strain is fairly good at picking up new genes. Because E. coli constantly evolves, it is peppered with genes from other strains found in animals and humans, giving it countless opportunities to gain lethality.
"It's just very unfortunate that in this case, it recombined and took on these (dangerous) genes and that it happened to do it in the food chain," he told The Associated Press (AP).
Scheutz said some previously seen related strains were also quite toxic but more samples were needed to get a better understanding of how this new strain behaves. "It's like looking at a family photo with three people and the 50 others are missing," he added.
To some, the DNA sequences found so far appear to be worrying enough.
Stephen Smith, a microbiologist at Trinity College in Dublin, said the new strain appears to stick to human intestines in a different way and that the bacteria might reproduce faster than other E. coli strains. More bacteria in the intestines could explain why the disease is so deadly, he said.
"It could be the bacteria's genes are causing it to produce more toxin, which may affect patients differently," Smith, who was not involved in the sequencing studies, told AP.
The toxin usually targets the kidney, triggering a severe E. coli complication. But in the European outbreak, many of those patients have also suffered from neurological problems including paralysis.
Frederick Blattner of the University of Wisconsin, said the toxin released in the German E. coli strain seemed extremely potent.
"With other strains, it can take a million of them in your stomach to make you sick," he told AP. "But with this bacteria, it might be possible to be infected with much lower numbers."
Researchers have also found that E. coli has at least eight genes that make it resistant to many antibiotics.
"That could give suggestions to doctors about what treatments to select for patients," said Bicheng Yang, a spokeswoman for BGI, the Chinese laboratory that sequenced the bacteria. In Germany, many patients with the most severe form of the disease, which involves kidney failure, have been treated with dialysis and blood transfusions.
"The next step is to do further tests at the molecular level to see what drugs might work," said Yang, adding that knowing more about the origins of the bacteria could help stop future outbreaks and avoid further mutations.
The DNA information could also help scientists determine how E. coli sticks to certain vegetables, and then stop it before it happens, said Gad Frankel, a microbiologist at Imperial College in London.
"It's possible we could develop inhibitors to prevent the interaction between E. coli and vegetables," Frankel told AP, explaining a biodegradable spray could theoretically be made to do the job.
"We can't stop evolution, but if we can learn today how and where it happens, we might be able to save lives in the future," said Smith.
The current outbreak has caused ailments in 3,255 people in 14 European countries and the United States and Canada, according to the WHO. All but five cases were in people from or who had visited Germany.
Many of these people are seriously ill with bloody diarrhea and haemolytic uraemic syndrome (HUS), a serious kidney ailment. The WHO said Saturday that 773 people from Germany has HUS, and another 40 had it in other countries.
"This wave of EHEC and haemolytic uraemic syndrome cases in Germany is the most significant recorded in the world to date," Nele Boehme, spokeswoman for the Federal Institute for Risk Assessment (BfR), told AFP.
The farm where the outbreak originated has been closed down and all of its products have been recalled. The cultivated sprouts came from a variety of products including lettuce, adzuki beans, mung beans, fenugreek, alfalfa and lentils.
German authorities said that the farm had done nothing wrong. The farm had "high hygiene standards," added Gert Lindemann, Lower Saxony agriculture minister.
Authorities late last week advised citizens to avoid eating uncooked tomatoes, cucumbers and lettuce. The scare has cost European farmers hundreds of millions of dollars. The Robert Koch Institute (RKI) still recommends not eating raw vegetable sprouts.
The European Commission has offered $303 million to farmers affected across Europe. Russia had initially banned import of all fresh vegetables from the whole of the 27-nation European Union until the issue was resolved. But Moscow agreed at a summit with the EU on Friday to lift the ban.
On the Net: