Reoccurring <i>Escherichia coli</i> O157:H7 Strain Linked to Leafy Greens–Associated Outbreaks, 2016–2019

Abstract

Genomic characterization of an Escherichia coli O157:H7 strain linked to leafy greens-associated outbreaks dates its emergence to late 2015. One clade has notable accessory genomic content and a previously described mutation putatively associated with increased arsenic tolerance. This strain is a reoccurring, emerging, or persistent strain causing illness over an extended period.