Eating Jimmy John’s sandwiches with cucumbers imported from Mexico was the likely cause of a Denver-area E. coli O157:H7 outbreak that occurred in October 2013, according to a new 27-page state investigative report. The investigation, by the Colorado Department of Public Health and Environment (CDPHE) and several local public health departments in the Denver area, identified nine E. coli infections associated with sandwiches purchased at Jimmy John’s outlets in Littleton, Lakewood, and Glendale that came with the Mexican cucumbers. Eight of the nine cases were laboratory-confirmed with matching pulsed-field gel electrophoresis (PFGE) and with multiple-locus variable number tandem repeat analysis (MLVA) patterns from E. coli O157:H7 isolated from stool samples. A ninth probable case was included in the outbreak. “To our knowledge, this is the first E. coli O157:H7 outbreak associated with cucumbers reported in the United States,” the investigative report states. “Public health and food safety officials should be aware that cucumbers may be contaminated with E. coli O157:H7, which could cause sporadic E. coli O157:H7 infections as well as outbreaks.” This is not the first time the privately held Jimmy John’s, based in Champaign, IL, and with 2,004 franchise locations in the U.S., has been linked to an outbreak. But past Jimmy John’s outbreaks have involved sprouts and, in one instance, sprouts and lettuce. CDPHE’s Laboratory Services Division found two E. coli O157:H7 cases on Oct. 21, 2013, with matching PFGE patterns and began checking the national PulseNet system to see if other states had any cases with similar DNA “fingerprints.” The pattern was common to one seen nationwide every year. It was not long before Colorado had matches to a Minnesota case involving ground beef and several in Arizona involving a child care center with a person-to-person contamination problem. At that point, CDPHE began to use MLVA testing for the finer level of comparison between isolates that it provides. By Oct.22, four Colorado cases were linked into a likely cluster. “Additional states had MLVA testing completed on E. coli O157:H7 cases with the matching PFGE pattern combination, none of which matched the MLVA pattern seen in the Colorado cases, further supporting that the Colorado cluster had a unique exposure,” the report states. For the Colorado investigation, a confirmed case was defined as a Colorado resident with onset of laboratory-confirmed E. coli O157:H7 infection with the outbreak MLVA pattern in October 2013. The one probable case was a Colorado resident with post-diarrheal HUS and positive E. coli O157 serology in October 2013. While going public with their outbreak report, CDPHE did not tell the public about the outbreak when it was occurring until Jimmy John’s patrons disclosed the event to a Denver television station. “CDPHE did not issue a press release for this outbreak as surveillance data and the investigation findings determined that there was not ongoing transmission or risk to the public,” the report reads. Before the secret leaked out, however, the CDPHE report acknowledges that the state was reaching out to surrounding states, local public health officials and hospitals seeking further reports for followups. It even covered the outbreak in its “Hot Topics in Epidemiology” newsletter, which it emails to public health officials. CDPHE notified Jimmy John’s corporate offices about the investigation on Oct. 23, 2013, and then allowed the public to remain in the dark for another week before confirming the TV reports. At the time, department officials said they suspected a “produce item” served by Jimmy John’s was the likely source of the outbreak. It’s likely most would have guessed sprouts as the problem since, at least five times since 2008, Jimmy John’s restaurants have served up contaminated sprouts involved in outbreaks. All three of the Jimmy John’s outlets involved in the outbreak used Denver-based Colo-Pac Produce Inc. as their cucumber supplier. The three restaurants and the produce supplier were subjected to unannounced inspections during the investigation. A traceback was conducted that found all the contaminated cucumbers came from the same lot and were available in the restaurants on the dates that contaminated product was consumed.