As of Tuesday, 96 people from five states have been infected with the strain of E. coli implicated in the latest outbreak, federal health agencies said. The last reported illness began on March 26.
The strain has emerged in Georgia, Kentucky, Ohio, Tennessee and Virginia, with the highest number of cases, 46, in Kentucky, the CDC said in a statement.
Eleven people have been hospitalized, but no deaths or cases of kidney failure have been reported. The patients range from 1 year old to 81 years old.
The Centers for Disease Control and Prevention, several states, the U.S. Department of Agriculture's Food Safety and Inspection Service, and the U.S. Food and Drug Administration are investigating the multistate outbreak of Shiga toxin-producing E. coli O103 infections.
The investigation has not identified a specific food item, grocery store or restaurant chain as the source of the infection.
Those infected get sick an average of 3 to 4 days after eating or drinking something that contains the bacteria, according to the CDC.
Symptoms include severe stomach cramps, diarrhea and vomiting. Some people with the infection may also get a type of kidney failure called hemolytic uremic syndrome, according to the CDC.
"State and local public health officials are interviewing ill people to determine what they ate and other exposures in the week before their illness started," said the CDC.
Last year, an E. coli outbreak linked to romaine lettuce sickened 62 people across 16 states and Washington, D.C.