The outbreak is thought to be over, but public health officials in the Seattle area continue to investigate the source of E. coli O157:H7 that infected at least 15 people and is linked to romaine lettuce.

Seattle – King County Public Health has been investigating the outbreak and seven associated Evergreens restaurants in King County, WA. The most recent illness in this outbreak started on Nov. 17, 2019, according to the public health department. Of the patients, 13 are from King County and two from Snohomish County.

The Washington outbreak has been classified as separate from two multistate outbreaks of E. coli O157:H7 infections. The U.S. Centers for Disease Control and Prevention yesterday declared the two multistate outbreaks over.

Genetic testing on isolates from 11 of the 15 patients in the Washington state outbreak indicates that the strains are closely related, suggesting a common source. The other four people who got sick were not specifically tested for E. coli, but their symptoms are suggestive of infection from E. coli O157:H7.

Illness onset dates for the patients in the Seattle area occurred from Nov. 8–17, 2019. Meal dates at the implicated restaurants were from Nov. 5–11, 2019. Three people were hospitalized. Everyone who reported illness has recovered.

The Seattle area investigation
From Nov. 21 to Dec. 12, 2019, Environmental Health investigators visited six Evergreens restaurant locations where the ill people reported eating. During their field inspections, investigators did not observe environmental or behavioral risk factors associated with the spread of E. coli, such as poor handwashing practices, improper time and temperature control of foods, or other types of risk factors that can be associated with E. coli infections. Out of an abundance of caution, Environmental Health investigators are visiting all 15 Evergreen restaurants in King County.

Public health officials say this local outbreak could be the result of a contaminated product delivered to and served at Evergreens. In addition, many of the people who became ill after eating at Evergreens also reported eating raw vegetables, including leafy greens, from sources other than Evergreens in the days prior to their illness, meaning they could share a separate source for their illness unrelated to Evergreens.

Investigators reviewed with staff at six locations, proper sanitizing practices to help prevent the spread of E. coli. In accordance with CDC’s recommendations, Evergreens restaurants discarded all romaine lettuce products from their stores, including romaine on the line and in coolers. Finally, management reviewed their sick policy with all employees.

As per protocol, public health investigators revisited six Evergreens restaurant locations where patients reported eating to confirm that these actions were taken.

The public health department has identified two employees who experienced symptoms consistent with an E. coli infection after eating at Evergreens but were not tested. However, there is no evidence indicating these people were the source of the outbreak. During their visits, investigators reviewed the requirement that restaurant employees are not allowed to work while having vomiting or diarrhea.

Officials collected samples of various produce from two Evergreens locations where ill people ate. E. coli testing of these food products at the Washington State Public Health Laboratory was negative.

Public Health is continuing to work with the Washington State Department of Agriculture and U.S. Food and Drug Administration on tracing back the distributors and sources for ingredients the people who became ill consumed in their meals.

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