June 1, 2016
CDC is collaborating with public health and regulatory officials in multiple states and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Shiga toxin-producing Escherichia coli O121 (STEC O121) infections.
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet, coordinated by CDC, is the national subtyping network of public health and food regulatory agency laboratories. PulseNet performs DNA fingerprinting on STEC bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks.
Thirty-eight people infected with the outbreak strain of STEC O121 have been reported from 20 states. A list of the states and the number of cases in each can be found on the Case Count Map page. WGS showed that isolates from ill people are closely related genetically. This close genetic relationship means that people in this outbreak are more likely to share a common source of infection.
Illnesses started on dates ranging from December 21, 2015 to May 3, 2016. Ill people range in age from 1 year to 95, with a median age of 18. Seventy-eight percent of ill people are female. Ten ill people have been hospitalized. No one has developed hemolytic uremic syndrome, a type of kidney failure, and no deaths have been reported.
This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after May 5, 2016, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. Please see the Timeline for Reporting Cases of E. coli O157:H7 Infection for more details.
Investigation of the Outbreak
Collaborative investigative efforts of state, local, and federal health and regulatory officials indicate that flour produced at General Mills’ Kansas City, Missouri facility is a likely source of this outbreak. This investigation is ongoing.
In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Sixteen (76%) of 21 people reported that they or someone in their household used flour in the week before they became ill. Nine (41%) of 22 people reported eating or tasting raw homemade dough or batter. Twelve (55%) of 22 people reported using Gold Medal brand flour. Three ill people reported eating or playing with raw dough at restaurants.
In an epidemiologic investigation, investigators compared the responses of ill people in this outbreak to those of people of similar age and gender reported to state health departments with other illnesses. Preliminary results of this investigation indicate an association between STEC O121 infection and someone in the household using Gold Medal brand flour to make something to eat.
Federal and state and local regulatory officials performed traceback investigations using package information collected from ill people and records collected from restaurants where ill people were exposed to raw dough. These investigations indicated that the flour used by ill people or used in restaurant locations was produced in the same week in November 2015 at the General Mills facility in Kansas City, Missouri. General Mills produces Gold Medal brand flour.
On May 31, 2016, General Mills recalled several sizes and varieties of Gold Medal Flour, Gold Medal Wondra Flour, and Signature Kitchens Flour due to possible E. colicontamination. The recalled flours were produced in the Kansas City facility during a time frame identified by traceback and sold nationwide. CDC recommends that consumers, restaurants, and retailers do not use, serve, or sell the recalled flours.
We will update the public when more information becomes available. CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview those people about foods they ate before they got sick.