Feb 15, 2012 (CIDRAP News) – An Escherichia coli O26 outbreak linked to raw clover sprouts served on Jimmy John's sandwiches has sickened 12 people in five states, the US Centers for Disease Control and Prevention (CDC) said today.
The 12 patients are from Iowa (5), Missouri (3), Kansas (2), Arkansas (1), and Wisconsin (1). All are female, and no hospitalizations or deaths have been reported. Patient ages range from 9 to 49 years. Among cases with available information, illness onset dates range from Dec 25, 2011, to Jan 15.
E coli O26 is one of six non-O157 strains that have accounted for a growing portion of E coli illnesses and in June will be classified by the US Department of Agriculture (USDA) as adulterants in ground beef.
The CDC said there is limited surveillance for E coli O26 and other non-O157 strains, so illnesses may go undiagnosed. The E coli O26 pulsed-field gel electrophoresis (PFGE) pattern in the outbreak has rarely been seen in PulseNet, a national molecular subtyping network for identifying foodborne bacteria.
The epidemiologic investigation found that 10 of 11 patients with available information had eaten at a Jimmy John's restaurant within 7 days of getting sick. Eight reported eating a sandwich with sprouts, and 9 ate a sandwich that contained lettuce.
A trace-back investigation by the Food and Drug Administration (FDA) identified a common lot of clover sprout seeds used to grow the sprouts at the Jimmy John's locations where the sick patients had dined. The FDA and its state partners found two sprouting facilities that used the same lot of clover seeds to grow sprouts for Jimmy John's restaurants.
The seed supplier notified the sprouting operations about the potentially contaminated lot of seeds and asked them to stop using it. Investigations are under way to find other locations that may have sold clover sprouts grown from the same seed lot.
The CDC said the probe is still ongoing, but preliminary results from the epidemiologic and trace-back investigations both point to eating clover sprouts at the Jimmy John's locations as the likely source of the outbreak.
Previous sprout outbreak investigations have shown that sprout seeds can become contaminated in several different ways, such as contact with contaminated water, improperly composted manure, or animal feces, the CDC said. It added that the seeds can also be contaminated during harvesting, distribution, and storage. Growing conditions can allow any bacteria on the seeds to grow rapidly.
Clover seeds are often produced for agricultural use, and some may not be processed for human consumption, according to the CDC.
In 2010, Jimmy John's customers in Illinois were among the 140 patients sickened in an alfalfa sprout–related outbreak that involved Salmonella serotype I 4,,12:i:-. The outbreak prompted Jimmy John's to switch from alfalfa to clover sprouts, according to a report last year from The Packer, an agricultural industry newspaper.
Contaminated raw sprouts have played a role in several foodborne illness outbreaks, including one linked to fenugreek seeds in Europe that sickened more than 3,100 people last year and was linked to 40 deaths.
Feb 15 CDC outbreak announcement
Feb 10, 2011, CDC final Salmonella outbreak update
Jan 12, 2011, Packer story