The Centers for Disease Control and Prevention (CDC) says that the multistate outbreaks of Shiga toxin-producing Escherichia coli O26 infections linked to Chipotle Mexican Grill restaurants appear to be over. The most recent illness reported to CDC started on Dec. 1, 2015.
The CDC, the Food and Drug Administration (FDA), the U.S. Department of Agriculture's Food Safety and Inspection Service, and public health officials in several states investigated two separate outbreaks of Shiga toxin-producing Escherichia coli O26 (STEC O26) infections. In the initial, larger outbreak, 55 people infected with the outbreak strain of STEC O26 were reported from 11 states. Twenty-one ill people were hospitalized. In the second, smaller outbreak, five people infected with a different strain of STEC O26 were reported from three states. One ill person was hospitalized. There were no reports of hemolytic uremic syndrome and no deaths in either outbreak.
Investigators used whole genome sequencing (WGS), an advanced laboratory technique, to get more detailed information about the DNA fingerprints of the STEC O26 bacteria that caused illness. Isolates tested from ill people in the second, smaller outbreak were not related genetically to isolates from ill people in the initial, larger outbreak.
The epidemiologic evidence collected during this investigation suggested that a common meal item or ingredient served at Chipotle Mexican Grill restaurants was a likely source of both outbreaks. The investigation did not identify a specific food or ingredient linked to illness. Most ill people in these outbreaks ate many of the same food items at a Chipotle Mexican Grill restaurant. When a restaurant serves foods with several ingredients that are mixed or cooked together and then used in multiple menu items, it can be more difficult for epidemiologic studies to identity the specific ingredient that is contaminated. Testing of multiple food items collected from Chipotle restaurant locations did not identify STEC O26. A review of Chipotle's distribution records by state and federal regulatory officials was unable to identify a single food item or ingredient that could explain either outbreak.