Four states affected in E. coli outbreak

E. coli. Photo by Janice Haney Carr/CDC

Tennessee has been added to the list of states affected by a multi-state outbreak of E. coli 0145 which has also affected Michigan, New York, and Ohio. The CDC has reported 23 confirmed and seven probable cases related to this outbreak in the following breakdown: Michigan (10 confirmed and 3 probable), New York (4 confirmed and 3 probable), Ohio (8 confirmed and 1 probable), and Tennessee (1 confirmed).

Investigators in New York obtained an E. coli O145 isolate from an unopened bag of romaine lettuce that matches the outbreak strain. A case-control study in Michigan found a significant association between illness and consumption of romaine lettuce from the same processing facility.

Among the confirmed and probable cases with reported dates available, illnesses began between April 10, 2010 and April 26. Infected individuals range in age from 13 years old to 31-years-old and the median age is 19 years. Sixty-six percent of patients are male. Among the 30 patients with available information, 12 (40 %) were hospitalized. Three patients have developed a type of kidney failure known as hemolytic-uremic syndrome, or HUS. No deaths have been reported. It takes an average of two to three weeks from the time a person becomes ill to the time when the illness is confirmed by laboratory testing and reported.

Local and state public health officials in all four states  are investigating human illnesses caused by Escherichia coli (E. coli) O145.

Multiple lines of evidence have implicated shredded romaine lettuce from one processing facility as a source of infection in this outbreak. This evidence includes the identification of the outbreak strain of E. coli O145 from an unopened package of shredded romaine lettuce obtained at an institution that received product from the processing facility linked to the outbreak. A case-control study in Michigan found a significant association between illness and consumption of romaine lettuce processed at the same facility that processed lettuce consumed by ill persons in New York, Ohio and Tennessee.

The lettuce processing company has issued a recall of lettuce produced at their facility as a result of the evidence obtained to date.  An additional recall was issued by a separate company that received lettuce from the same farm as the processing company linked to the outbreak.

Updates on the progress of this investigation will be shared as information becomes available.

Clinical Features/Signs and Symptoms

Most people infected with E. coli develop diarrhea (often bloody) and abdominal cramps 2-8 days (average of 3-4 days) after swallowing the organism, but some illnesses last longer and can be more severe. Infection is usually diagnosed by culture of a stool sample. Many clinical laboratories do not test for non-O157 STEC, such as E. coli O145, because identifying it is more difficult than for E. coli O157. Most people recover within a week, but some develop a severe infection. HUS can begin as the diarrhea is improving and can occur in people of any age but is most common in children under five and the elderly.