In February 2020 the CDC announced an investigation of an outbreak of E. coli O103 linked to consumption of clover sprouts on sandwiches sold at Jimmy John's restaurants. On April 22, 2020 investigators declared the outbreak over. There were 51 reported cases in 10 states. Three people were hospitalized. There were no deaths. Dates of illness onsets ranged from January 6, 2020 to March 15, 2020.

Information gathered indicated that clover sprouts were the source of the outbreak. On March 16, 2020, Chicago Indoor Garden recalled all products containing red clover sprouts. FDA traceback showed that a common seed lot was used to grow the sprouts recalled by Chicago Indoor Garden. The same seed lot was also used to grow sprouts linked to an outbreak of the same strain of E. coli O103 infections in 2019.

WGS analysis of isolates from 39 ill people was performed; the isolate from 1 ill person predicted antibiotic resistance to streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole, and 38 isolates from ill people did not show evidence of antibiotic resistance. Standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway. These findings do not affect treatment guidance since antibiotics are not recommended for patients with STEC O103 infections.

On April 22, 2020 the CDC declared the outbreak over.