Avoid All Romaine Lettuce, CDC Says

Updated: December 10, 2018 at 12:30 PM EST

On November 21, 2018, The US Centers for Disease Control and Prevention (CDC) announced a multistate outbreak of Shiga toxin producing-E coli O157:H7 and advised Americans to avoid consuming any romaine lettuce until a source could be determined.

The CDC is working alongside health officials in several states, the Public Health Agency of Canada, and the US Food and Drug Administration (FDA) to investigate this outbreak linked with lettuce.

On November 28, 2018, the FDA announced that preliminary evidence indicates that the likely source of the outbreak is romaine lettuce that was harvested in the Central Coast growing regions of northern and central California. The specific areas identified include Monterey, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura. At this time it is no longer necessary to avoid lettuce harvested in other growing regions or from a greenhouse.

As of December 6, 2018, a total of 52 Americans across 15 states have fallen ill as well as several Canadians in the provinces of Quebec and Ontario.

The American cases have an onset of illness ranging between October 8, 2018, and November 18, 2018. Those who have become infected range in age from 1 to 84 years, with a median age of 30. Sixty-nine percent are female. Data is available for 45 of the individuals and indicate that 19 (42%) have been hospitalized, including 2 individuals who developed hemolytic uremic syndrome. No deaths have been reported at this time.

Illnesses that occurred after November 14, 2018, may not have been reported yet due to the E coli reporting timeline.

As part of the epidemiologic investigation, public health officials have interviewed the individuals who have fallen in about their consumption and exposures in the week prior to becoming ill. In total, 25 individuals were interviewed and 22 (88%) reported eating romaine lettuce, including different types of romaine lettuce from several restaurants, as well as at home.

Whole genome sequencing has indicated that the outbreak strain has a genetic resemblance to the E coli strain that was isolated from ill individuals during the 2017 outbreak linked with leafy greens in the United States and romaine lettuce in Canada.

However, the current outbreak is not related to the spring romaine lettuce outbreak, as they have different DNA fingerprints.

“Consumers can avoid eating and discard romaine. [The] industry can contribute greatly to containing and stopping [the] outbreak by voluntarily withdrawing romaine products from [the] market and withholding distribution until we can ensure outbreak is over or identify [a] specific source of contamination,” Scott Gottlieb, MD, FDA Commissioner said in a tweet (see below).

Consumers can avoid eating & discard romaine. Industry can contribute greatly to containing & stopping outbreak by voluntarily withdrawing romaine products from market & withholding distribution until we can ensure outbreak is over or identify specific source of contamination.

— Scott Gottlieb, M.D. (@SGottliebFDA) November 20, 2018

As a result of this outbreak, the FDA has announced that romaine lettuce sold to consumers will require a label that indicates the location and date of the harvest or if the lettuce was grown in a greenhouse.

Antibiotics are not recommended for the treatment of E coli O157 infections in both confirmed and suspected cases as studies have shown that administering antibiotics might increase the risk of developing hemolytic uremic syndrome.

This is an ongoing investigation and the CDC will provide more information as it becomes available.

For the most recent case counts associated with the Shiga Toxin Producing E coli O157:H7 Outbreak linked to romaine lettuce, check out the Contagion® Outbreak Monitor.