Investigation Details
Posted March 11, 2021
This outbreak is over. Always follow the four steps to food safety: clean, separate, cook, chill.
CDC, public health and regulatory officials in several states, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) collected and analyzed different types of data but were unable to identify the food source of this multistate outbreak of E. coli O157:H7 infections.
As of March 11, 2021, this outbreak is over.
Epidemiologic Data
As of March 10, 2021, a total of 22 people infected with the outbreak strain were reported from 7 states (see map). Illnesses started on dates ranging from December 18, 2020, to January 12, 2021 (see timeline).
Sick people ranged in age from 10 to 95 years, with a median age of 28, and 68% were female. Of 20 people with information available, 11 were hospitalized. Of 18 people with information, 3 developed a type of kidney failure called hemolytic uremic syndrome (HUS). One death was reported from Washington.
State and local public health officials interviewed people about the foods they ate in the week before they got sick. CDC analyzed the interview data and did not identify a specific food item as a potential source of this outbreak. People reported eating a variety of food items, including leafy greens, broccoli, cucumbers, and strawberries. However, none of the food items were reported significantly more by sick people in this outbreak when compared to healthy people in the FoodNet population survey.
Laboratory and Traceback Data
Public health investigators used the PulseNet system to identify illnesses that were part of this 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 were closely related genetically. This means that people in this outbreak likely got sick from eating the same food.
WGS predicted that bacteria from 14 people’s samples were resistant to all of the following antibiotics: chloramphenicol, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently conducting standard antibiotic resistance testing. These findings do not affect treatment options for people in this outbreak. This is because antibiotics are not recommended for treating E. coli O157:H7 illnesses.
WGS also showed that this outbreak strain was previously linked to various sources, including romaine lettuce and recreational water.
FDA conducted traceback investigations on several produce items but did not identify a common source or potential point of contamination.
CDC, public health and regulatory officials in several states, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) are collecting different types of data to identify the food source of a multistate outbreak of E. coli O157:H7 infections.
Epidemiologic Data
As of February 1, 2021, a total of 16 people infected with the outbreak strain have been reported from 5 states. This map shows where sick people live.
Illnesses started on dates ranging from December 23, 2020, to January 7, 2021. This chart shows when people got sick. Recent illnesses may not yet be reported as it usually takes 2 to 4 weeks to link illnesses to an outbreak.
Sick people range in age from 10 to 95 years, with a median age of 31, and 88% are female. Of 12 people with information available, 9 have been hospitalized. Of 11 people with information, 3 developed a type of kidney failure called hemolytic uremic syndrome (HUS). One death has been reported from Washington.
State and local public health officials are interviewing people to find out what foods they ate in the week before they got sick.
Laboratory and Traceback Data
Public health investigators are using the PulseNet system to identify illnesses that may be part of this 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 eating the same food.
WGS also showed that this outbreak strain has been previously linked to various sources, including romaine lettuce and recreational water. More information is needed to identify the source of this outbreak.
