WASHINGTON — The Centers for Disease Control and Prevention and the US Food and Drug Administration have begun gathering data as part of an investigation into a multistate outbreak of E. coli O121 linked to cake mix. A single brand or type of cake mix has not been linked to the illnesses, the CDC said.

According to the CDC, 16 people have been infected (7 hospitalized) with the outbreak strain of E. coli O121 as of July 27. One person has developed a type of kidney failure called hemolytic uremic syndrome (HUS), but no deaths have been reported. Outbreaks have been reported from 12 states, with illnesses starting on dates ranging from Feb. 26 to June 21. The outbreak has sickened people as young as 2 and as old as 73, with a median age of 13. All the illnesses have been in females, the CDC said.

“State and local public health officials are interviewing people about the foods they ate in the week before they got sick,” the CDC said. “Of the eight people interviewed, six (75%) reported tasting or eating raw batter made with a cake mix. People reported buying different varieties and brands of cake mix.”

The CDC said public health investigators are using the PulseNet system to identify illnesses that may be part of the outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples are closely related genetically. This means that people in this outbreak likely got sick from the same food.

In addition, the FDA is conducting a traceback investigation using purchase records from locations where sick people bought cake mix to try to determine a common cake mix brand or production facility.