Tuesday, December 12, 2006; 12:00 AM
MONDAY, Dec. 11 (HealthDay News) -- Investigators are no closer to determining the source of an outbreak ofE. colithan they were when the first of 64 people in the Northeast became ill in early November, federal health officials said Monday.
Tests on green onions, believed to have been a possible cause, were negative, they said.
But the outbreak, linked to Taco Bell restaurants, may be winding down. No new cases have been added to those reported in five states since late last week, the U.S. Centers for Disease Control and Prevention reported.
Dr. Christopher Braden, an epidemiologist with the U.S. Centers for Disease Control and Prevention, told a news teleconference there may yet still be unconfirmed cases of people sickened byE. coli.
"We are not ready to say it's absolutely over, but we haven't had any new cases in the last few days," he said.
Last week, officials from the CDC and U.S. Food and Drug Administration were focusing on green onions as the likely source of the bacterial outbreak linked to patrons who ate at Taco Bell restaurants. But laboratory tests haven't been able to prove such a link.
But Taco Bell isn't taking any chances. The food chain Saturday announced it had removed all green onions, also called scallions, from its 5,800 restaurants nationwide. "We're focused on working with the authorities to find the root cause," said Rob Poetsch, a spokesman for Yum! Foods, which owns Taco Bell.
"We have obtained samples from the laboratory that Taco Bell used to test samples of green onions," Dr. David Acheson, chief medical officer at the FDA's Center for Food Safety and Applied Nutrition, said during the teleconference. "Testing of these samples was negative forE. coli.
"We have been unable to confirm that green onions are the source of the outbreak. We have not ruled out any food items, including green onions," Acheson added.
Acheson said testing of a sample of white onions from a Taco Bell on New York's Long Island by county health officials found the produce was contaminated withE. coli, but not the same strain as the one identified in the outbreak. "It doesn't match the outbreak strain or any strain associated with the illnesses," Acheson said.
As of Monday afternoon, the CDC reported 64 confirmed cases ofE. coliinfection in five states. New Jersey has 28 confirmed cases; New York has 22; Pennsylvania has 11, Delaware has two, and South Carolina has one. The South Carolina patient ate at a Taco Bell in Pennsylvania, according to the CDC.
Of the confirmed cases on the CDC list, 82 percent of the victims required hospitalization and 13 percent developed a form of kidney failure called hemolytic-uremic syndrome, the agency said.