Officials Working to Quell Largest E. coli Outbreak Since 2006

On Friday, April 27, 2018, the US Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) provided an update on the growing multistate outbreak of Escherichia coli (E. coli) O157:H7 that has been linked with romaine lettuce.

On the media call, Matthew Wise, PhD, MPH, deputy branch chief for Outbreak Response at the CDC, confirmed that the total number of associated illnesses is just under 100, with 98 individuals falling ill across 22 states.

Officials have identified Harrison Farms as the source of the whole heads of romaine lettuce that were sold to a prison in Nome Alaska, where 8 inmates fell ill after eating the contaminated lettuce. It has been stressed that the farm has only been tied to those cases, though, and not the others.

“We have not yet gone to the farm to visit. We will be making an assignment to go out to the farm to visit and find out what else they are growing. At this point we aren’t seeing any other implicated products,” Stic Harris, DVM, MPH, director of the FDA’s Coordinated Outbreak Response and Evaluation Network, said on the media call. “To reiterate, these are only the whole head romaine portion of the outbreak; this facility was the only place we actually saw the disease linked to whole head romaine.” The farm has since ceased lettuce production.

Officials are currently looking into over 2 dozen farms as potential sources for the other cases.

“There’s a perception that when we do traceback that each leg is a direct line down; in this case, you’re looking at a web,” Dr. Harris said. “We’re trying to find out where all [the cases] are coming from. We’re trying to get them all mapped out and identify specific causes. We might not even get there; a lot of times we don’t, but we’re going to try.”

Dr. Wise added that about half (53%) of those who have fallen ill have required hospitalization, a percentage that is “higher than what we usually see with E. coli outbreaks, which is about 30%.” Ten of these individuals developed hemolytic uremic syndrome (HUS), a type of kidney failure.

“The group of 10 people diagnosed with HUS range in age from 13 to 87 years; three are children,” Dr. Wise said. “There are more complications in children in these outbreaks.” However, he stressed, “Everybody should be concerned. This is not the time to tailor advice to a risk group; everyone should avoid eating romaine lettuce.”

As for why more individuals are ending up in the hospital, according to Dr. Wise, laboratory testing has confirmed that the outbreak strain “is one that tends to cause more severe illness based on the kind of toxin it produces.”

This outbreak is the “largest multistate outbreak of E. coli since the 2006 outbreak that was linked to spinach,” he said. A total of 199 individuals were infected in that outbreak, spanning 26 states. The 2006 outbreak strain was similar to the one seen in the current outbreak, according to Dr. Wise, resulting in more severe infection. As such, about 51% of those infected in the 2006 outbreak required hospitalization and 16% went on to develop HUS.

“We’re still working to elucidate the remainder of the outbreak," Dr. Harris concluded. “The [source of the] whole head romaine lettuce has been identified. The remainder of infections [have been linked with] chopped bag romaine and we’re continuing to work to identify the other field [sources] and ensure that Americans are safe.”

Dr. Wise added that the advice to consumers remains the same—stay away from romaine lettuce. “People should not be eating any type of romaine lettuce unless they know for sure that it’s not grown in the Yuma growing region,” he said. “If in doubt, don’t buy it and don’t eat it.”

For the most recent case counts and states affected in the multistate E. coli outbreak linked to romaine lettuce, be sure to visit the Contagion^® Outbreak Monitor.