Two people who attended a wedding in Minneapolis on September 10, 2011, were subsequently diagnosed with E. coli O157:H7, strain MN1252ECB13. One case was hospitalized for 5 days. Neither developed hemolytic uremic syndrome. One case was a 12-year-old male and the other a 6-year-old female. The two cases did not appear to know each other.

The wedding was held at a rental room of a Mexican restaurant. The only food items served at the event were beef, rice, hot sauce, and cake. The cake was purchased at an unknown Mexican bakery. The other items were prepared by relatives in private homes. The beef served at the event was purchased by the groom or a relative as a whole cow and slaughtered at one of the live animal markets in South St. Paul. Frozen cooked beef from the same cow was picked up from a case's home. It was negative for E. coli O157:H7 at the Minnesota Department of Agriculture laboratory. Attempts to contact the groom for additional information about wedding attendees and foods served were unsuccessful.

A third case of E. coli O157:H7 with PFGE pattern MN1252ECB13 was identified in routine disease surveillance. This case was a Hispanic child from Minneapolis with illness onset on October 3; however, the case did not attend the wedding and denied any exposure to a live animal market and therefore was not included as an outbreak associated case.