New E. coli strain blamed for multiple outbreaks of foodborne illness 

A new strain of E. coli is to blame for multiple outbreaks of foodborne illness, according to new research published by the Centers for Disease Control and Prevention (CDC).

Researchers found that a specific strain of the bacteria associated with leafy greens “has been the source of ongoing enteric illness since late 2016.” The study, published Wednesday, said the strain likely emerged in late 2015 and has since been the cause of numerous outbreaks.

Researchers analyzed E. coli from a large outbreak in 2019 that caused 167 cases of foodborne illness and hospitalized 85 people from 27 states, as well as other "closely related" strains. The study found that the new strain includes a mutation of an “arsenical resistance operon repressor,” meaning that it could have a higher advantage in environments with increased levels of arsenic, like in soils and water sources.

“This finding underscores the potential need to routinely screen enteric bacterial strains for heavy metal resistance determinants, as well as to consider heavy metal levels in soil as part of traceback investigations,” the study states.

The study noted that an additional outbreak associated with the strain emerged in 2020, which resulted in 40 infections in 19 states and 20 hospitalizations. The CDC has classified the strain as a reoccurring, emerging or persistent strain, meaning that it could “reoccur and periodically cause acute outbreaks” or "emerge and increase in frequency or persist and cause illnesses over periods of months or years,” according to the agency.

Symptoms of an E. coli infection include severe stomach cramps, diarrhea and vomiting, according to the CDC. While most people recover in five to seven days, some cases could be life-threatening and result in severe illness.