LONDON – An entirely new super-toxic bug is causing the frightening food poisoning outbreak that has sickened at least 1,600 people and killed 18, researchers and global health officials said Thursday.
The DNA of the new E. coli strain, believed to have contaminated salad vegetables, was analyzed by Chinese and German scientists. It contains several genes that cause antibiotic resistance and is similar to a strain that causes serious diarrhea and is found in the Central African Republic, according to a statement from the Shenzhen, China-based laboratory, BGI. Those scientists were working together with the University Medical Center Hamburg-Eppendorf.
"This is a unique strain that has never been isolated from patients before," Hilde Kruse, a food safety expert at the World Health Organization, told The Associated Press. The new strain has "various characteristics that make it more virulent and toxin-producing" than the many E. coli strains people naturally carry in their intestines.
Preliminary genetic sequencing suggests the strain is a never before seen combination of two different E. coli bacteria, with aggressive genes that could explain why the outbreak appears to be so massive and dangerous, the agency said.
Researchers have so far been unable to pinpoint the food source of the illness, which has now spread to at least 10 European countries and fanned uncertainty about eating tomatoes, cucumbers and lettuce. The germ has caused 499 to develop a kidney failure complication. Germany is hardest hit.
Fearful of the outbreak spreading east to Russia, the country extended a ban on vegetables to the entire European Union from just Germany and Spain, a move the bloc quickly called disproportionate.
Kruse said it's not uncommon for bacteria to continually mutate, evolving and swapping genes. It is difficult to explain where the new strain came from, she said, but strains of bacteria from both humans and animals easily trade genes, similar to how animal viruses like Ebola sometimes jump into humans.
"One should think of an animal source," Kruse said. "Many animals are hosts of various types of toxin-producing E. coli." Some scientists suspect the deadly E. coli might have originated in contaminated manure used to fertilize vegetables.
