- Associated Press - Thursday, June 2, 2011

LONDON (AP) - A 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 new E. coli strain that is 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.


However, Dr. Robert Tauxe, a foodborne disease expert at the U.S. Centers for Disease Control and Prevention, questioned whether the strain is entirely new and said it had previously caused a single case in Korea. He said genetic fingerprints may vary a little but that “this strain is rare enough that a lot of people haven’t heard of it.”

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.