Outbreak: Toxic Tacos

December 7, 2006

Update 12/12/06  Download new NY DOH Alert

Several Taco Bell restaurants in our area have been shut down recently due to an outbreak of E. Coli O157:H7.  At least 22 people are infected, and most are under age 18.  Interestingly, at least 2 Taco Bell employees have been found to carry the bacteria but are asymptomatic.

The vector is usually undercooked infected meat.  Symptoms usually present within 3-4 days of ingestion. The department of health has issued a warning to physicians to consider this diagnosis if a patient presents with bloody diarrhea or hemolytic-uremic syndrome (HUS).

If a patient presents, his/her information should be reported to the NY City Department of Health.  Specifically:  providers should request testing stool for Shiga toxin producing E. coli and request the microbiology lab to attempt to grow the bacteria in sorbitol-MacConkey (SMAC) agar.

Hemoytic uremic syndrome is usually a disease afflicting young children, but can often present in the elderly.  Patients usually present with acute onset bloody diarrhea and fever, followed several days later by acute renal failure, thrombocytopenia, and microangiopathic hemolytic anemia.  Occassionally, the syndrome is preceded by a URI instead of a diarrheal illness.

HUS is associated with many infectious agents other than E. Coli O157:H7. Shigella, yersinia, salmonella, campylobacter, some strep species, and some viruses have been associated with the syndrome.  It is thought to be caused by immune complex deposition.  Prognosis in children is 5-15% mortality rate, but mortality rates increase dramatically with increasing age.

Younger adults may present with thrombotic thrombocytopenia purpura associated with E. Coli O157:H7.  It is a derangement of the coagulation cascade in which platelet plugs obstruct small vessels.  The inciting event is thought to be the inability to properly degrade von willebrand factor multimers.  It is more commonly associated with second trimester of pregnancy and HIV disease, and has an almost 100% mortality rate.


Currently, plasmapheresis and plasma exchange are the treatment of choice for both syndromes.  It should be started as soon as the diagnosis is proposed, even before the patient has left the emergency department.  Antibiotics are CONTRAINDICATED, as they have been associated with increased production of the causative verotoxin.

NY City DOH Notification

One comment on “Outbreak: Toxic Tacos

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    admin on

    Update: As per today’s 12/8/06 New York Times “health officials and food distributors zeroed in yesterday on a California farm as the possible source of the contaminated green onions that have sickened Taco Bell customers, the E. coli outbreak widened considerably, with cases reported for the first time in New York City, Delaware, South Carolina and Utah.
    In all, the number of cases that have been reported ballooned, to at least 169 yesterday, with most concentrated on Long Island and in New Jersey.”

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