A total of 26 confirmed and 7 probable cases related to this outbreak have been reported by the CDC from 5 states since March 1, 2010. The number of ill persons identified in each state with this strain is: MI (11 confirmed and 2 probable), NY (5 confirmed and 2 probable), OH (8 confirmed and 3 probable), PA (1 confirmed), and TN (1 confirmed). The reported cases in Tennessee and Pennsylvania do not reflect expansion of the outbreak but retrospective identification of cases using the PulseNet system – these cases are part of the original cluster due to the original implicated lot of lettuce from March.
The bacteria responsible for this outbreak are referred to as Shiga toxin-producing E. coli, or STEC. STECs have been associated with human illness, including bloody diarrhea and HUS. STEC bacteria are grouped by serogroups (e.g., O157 or O145). The STEC serogroup found most commonly in U.S. patients is E. coli O157. Other E. coli serogroups in the STEC group, including O145, are sometimes called “non-O157 STECs.” Currently, there are limited public health surveillance data on the occurrence of non-O157 STECs, including E. coli O145; therefore, E. coli O145 may go unreported. Because it is more difficult to identify than E. coli O157, many clinical laboratories do not test for non-O157 STEC infection.
Among the confirmed and probable cases with reported dates available, illnesses began between April 10, 2010 and April 26, 2010. Infected individuals range in age from 13 years old to 31 years old and the median age is 19 years. Sixty-four percent of patients are male. Among the 30 patients with available information, 13 (39%) were hospitalized. Three patients have developed a type of kidney failure known as hemolytic-uremic syndrome, or HUS. No deaths have been reported.