More Contaminated Lettuce / USA

E. COLI VTEC NON-O157 - USA (04): O145, LETTUCE
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A ProMED-mail post

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International Society for Infectious Diseases


Date: Tue 12 May 2010
Source: CDC, E. coli Outbreak Investigations [edited]



Local and state public health officials in Michigan, New York, Ohio,
and Tennessee are investigating human illnesses caused by _E. coli
O145. CDC is supporting these investigations and facilitating regular
communication and information sharing between the states and with the
Food and Drug Administration (FDA).

As of 11 May 2010, a total of 23 confirmed and 7 probable cases
related to this outbreak have been reported from 4 states since 1 Mar
2010. The number of ill persons identified in each state with this
strain is: MI (10 confirmed and 3 probable), NY (4 confirmed and 3
probable), OH (8 confirmed and 1 probable), and TN (1 confirmed).

Among the confirmed and probable cases with reported dates available,
illnesses began between 10 Apr 2010 and 26 Apr 2010. Infected
individuals range in age from 13 years old to 31 years old and the
median age is 19 years. 66 percent of patients are male.

Among the 30 patients with available information, 12 (40 percent)
were hospitalized. 3 patients have developed a type of kidney failure
known as hemolytic-uremic syndrome, or HUS. No deaths have been reported.

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 USA patients is O157. Other 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 O145; therefore, it 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.

Investigators are using pulsed-field gel electrophoresis (PFGE), a
type of DNA fingerprint analysis of _E. coli_ bacteria obtained
through diagnostic testing to identify cases of illness that might be
part of this outbreak. This testing is done in public health
laboratories as part of the PulseNet network. Investigators have
established a common definition of confirmed and probable cases
related to this outbreak.

Confirmed cases are persons with:
1. _E. coli_ O145 infection, or infection with O Group pending, and
2. an illness onset on or after 1 Mar 2010, and
3. a DNA fingerprint matching the outbreak strain; and
4. an epidemiologic link to the outbreak.

Probable cases are persons with an epidemiologic link to the outbreak and
1. E. coli O145 infection with an illness onset on or after 1 Mar
2010 regardless of DNA fingerprint pattern, and/or
2. hemolytic-uremic syndrome; and/or
(3) a laboratory isolate positive for Shiga toxin 2 [stx2] or isolate
positive for Shiga toxin, but toxin type is unknown or pending.

Current status of the investigation
-----------------------------------
Multiple lines of evidence have implicated shredded romaine lettuce
from a single 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.

This investigation is ongoing. At this time, local, state, and
federal health officials are involved in many different types of
investigative activities, including:
- Conducting surveillance for additional illnesses that could be
related to the outbreak.
- Conducting epidemiologic studies that include gathering detailed
information from persons who were ill persons (cases) and from
healthy persons (controls) about foods recently eaten and other exposures.
- Gathering and testing food products that are suspected as possible
sources of infection to see if they are contaminated with bacteria.
- Following any epidemiologic leads gathered from interviews with
patients, food purchase information, or from patterns of processing,
production and/or distribution of suspected products.

--
Communicated by:
ProMED-mail


[It is now stated that there is "smoking" lettuce, that is, the
alleged vehicle for transmission has been shown to be identical to
the human clinical isolates.

We await further epidemiological information from this outbreak,
which is likely to be significantly underreported because the
outbreak strain is not O157. - Mod.LL]

[see also:
E. coli VTEC non-O157 - USA (03): O145, lettuce, recall 20100507.1483
E. coli VTEC non-O157 - USA (02): (OH, MI, NY) O145 20100505.1460
E. coli VTEC non-O157 - USA: (MI, OH) 20100427.1358
2008
----
E. coli VTEC non-O157, restaurant - USA (04): (OK), O111 20081201.3779
E. coli VTEC non-O157, restaurant - USA: (OK), O111 20080902.2748
E. coli VTEC non-O157, past. ice cream, 2007 - Belgium: Antwerp 20080218.0655
2007
----
E. coli VTEC non-O157, beef sausage - Denmark 20070602.1784
E. coli VTEC non-O157, 2000-2005 - USA (CT) 20070118.0240
2006
----
E. coli VTEC non-O157, lettuce - USA (UT)(02): background 20060905.2523
E. coli VTEC non-O157, lettuce - USA (UT) 20060904.2521
E. coli VTEC non-O157 - Norway (03) 20060416.1133
E. coli VTEC non-O157 - Norway 20060329.0947
E. coli VTEC non-O157, minced beef - Norway 20060304.0680
2005
----
E. coli O145, fatal - Slovenia 20050916.2739
2003
----
E. coli, VTEC non-O157 - UK (Scotland): correction 20030828.2166
E. coli, VTEC non-O157 - UK (Scotland) 20030825.2144
2001
----
E. coli O26 - South Korea 20010509.0896
1999
----
E. coli O111, diarrhea - USA (Texas) 19990707.1134
1997
----
E. coli, non-0157 - Belgium 19970610.1215]
...................................ll/mj/mpp

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