Reoccurring Escherichia coli O157:H7 Strain Linked to Leafy Greens-Associated Outbreaks, 2016-2019

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 ac-cessory genomic content and a previously described mu-tation putatively associated with increased arsenic toler-ance. This strain is a reoccurring, emerging, or persistent strain causing illness over an extended period.

Automated summary

Genomic analysis reveals that the emergence of an Escherichia coli O157:H7 strain associated with leafy greens outbreaks can be traced back to late 2015. One specific clade shows unique genomic features and a previously identified mutation that may be related to increased tolerance to arsenic. This strain is persistent, recurring, or emerging, causing illness over an extended period.