Multi- state Outbreak of E-coli 0157
Infections, November-December 2006
As of Wednesday, December 13, 2006, 71 persons have become
ill with Escherichia coli 0157:H7 associated with eating contaminated
lettuce at Taco Bell restaurants in the northeastern United States. Cases have
been reported to CDC from five states: New Jersey (33), New York (22), Pennsylvania (13), Delaware (2) and South Carolina (1). Other cases of illness are under
investigation by state public health officials. Among the 71 persons with
illness, 53 (75 %) were hospitalized and 8 (11%) developed a type of kidney
failure called hemolytic-uremic syndrome (HUS). Illness onset dates have ranged
from November 20-December 6. New cases have declined substantially. The last
week of November was the peak time when persons became ill.
Of the 71 persons with illness, 48 have been confirmed as
cases. Strains are routinely “DNA fingerprinted” by laboratories in all 50
states as part of CDC’s PulseNet Network (the network of public health
laboratories that sub-type bacteria). E. coli 0157 strains from other
cases are being tested by PulseNet. As a result of testing, cases found with
the outbreak strain “fingerprint” are being re-classified as confirmed cases
and cases with an unrelated “fingerprint” pattern are being dropped from the
case count. There have been no illnesses with onset within the past 5 days
among identified cases, including suspects; therefore, the outbreak has
ended.
Concerning the outbreak of E. coli O157 infections
associated with Taco John's restaurants, Minnesota and Iowa are reporting 27
and 50 associated illnesses, respectively. Isolates from these outbreaks cases
of E. coli O157 demonstrate indistinguishable patterns, confirming that
the two clusters are linked. However, this pattern is distinct from the Taco
Bell outbreak pattern. One other matching isolate from Wisconsin has been
identified. Investigators in Minnesota and Iowa have independently identified
lettuce as the contaminated food vehicle in that outbreak. Trace back efforts
are underway.
CDC is working with state and local
health officials, the Food and Drug Administration (FDA), the Department of
Agriculture (USDA), and the restaurant chain to determine what food caused the
outbreak. Public health investigators have identified a few ingredients that
were consumed more often by ill persons than well persons and were
statistically linked with illness: lettuce, cheddar cheese, and ground beef.
This analysis also indicates that onions of any type are not linked to this
outbreak. Evaluation of data indicates that shredded lettuce consumed at Taco
Bell restaurants in the northeastern United States was the most likely source
of the outbreak. Because multiple Taco Bell restaurants were involved
during the same time period, contamination of lettuce likely occurred before
reaching the restaurants. Health officials and the restaurant chain are
working collaboratively to learn more about the shredded lettuce to determine
how it may have become contaminated.
E. coli O157 causes
diarrhea that is often bloody and accompanied by severe abdominal cramps, but
fever is typically absent or mild. Persons who have developed such symptoms
after eating at a Taco Bell restaurant in an affected state are advised to
consult a physician and to inform their local health department.
For more information on E. coli
infection and this outbreak, please refer to the following website: http://www.cdc.gov/ecoli/
