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Investigation Update: Multistate Outbreak of E. coli O157:H7 Infections Associated with Cheese

Updated November 16, 2010

Today's Highlights

  • Laboratory testing conducted by the New Mexico Department of Health on an unopened package of Bravo Farms Dutch Style Gouda Cheese purchased from a Costco retail location has identified E. coli O157:H7 matching the outbreak strain. This is the first confirmation from an unopened cheese sample, and is consistent with previous laboratory testing that also identified E. coli 0157:H7 in tests conducted on opened packages of Bravo Farms Dutch Style Gouda Cheese from case patients’ homes.
  • Thirty-seven persons infected with the outbreak strain of E. coli O157:H7 have been reported from five states since mid-October. The number of ill persons identified in each state with this strain is as follows: AZ (19), CA (3), CO (10), NM (3) and NV (2). There have been 15 reported hospitalizations, 1 case of hemolytic uremic syndrome (HUS), and no deaths.

Infections with the Outbreak Strain of E. coli 0157:H7 by statestate map

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Infections with the outbreak strain of E. coli O157:H7 by known or estimated illness onset, October 2010 - presentepi curve

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Investigation of the Outbreak

CDC is collaborating with public health officials in Arizona, California, Colorado, New Mexico, Nevada, the U.S. Department of Health and Human Services’ Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) to investigate a multistate outbreak of human infections due to E. coli O157:H7. This is a rare strain of E. coli O157:H7 that has never been seen before in the PulseNet database. PulseNet is the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.

Thirty-seven persons infected with the outbreak strain of E. coli O157:H7 have been reported from five states. The number of ill persons identified in each state with this strain is as follows: AZ (19), CA (3), CO (10), NM (3) and NV (2). Dates of illness onset range from October 16, 2010 through October 27, 2010. Patients range in age from 1 to 85 years and the median age is 16 years. There have been 15 reported hospitalizations, 1 case of hemolytic uremic syndrome (HUS), and no deaths.

The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after October 22, 2010 might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks.

Current Status of the Investigation

Laboratory testing conducted by the New Mexico Department of Health on an unopened (intact) package of Bravo Farms Dutch Style Gouda Cheese purchased from a Costco retail location has identified E. coli O157:H7 matching the outbreak strain. This is the first confirmation from an unopened cheese sample, and is consistent with previous laboratory testing conducted on two opened packages of the Bravo Farms Dutch Style Gouda Cheese purchased at Costco, which also identified E. coli O157:H7 matching the outbreak strain. These opened packages were from two different case patients’ homes. Testing on two additional opened packages from other case patients’ homes is in process.

FDA is continuing to work with its state partners to investigate Bravo Farms and to identify potential sources of contamination. FDA has collected product samples for testing.

Additional investigative activities are ongoing and include:

  • Conducting surveillance for additional illnesses that could be related to the outbreak.
  • Gathering and testing food products that are suspected as possible sources of infection to see if they are contaminated with bacteria.
  • Following epidemiologic leads gathered from interviews with patients, food purchase information, or from patterns of processing, production and/or distribution of suspected products.
  • Investigating where in the distribution chain the point of contamination could have occurred.

Costco is cooperating and assisting with this ongoing investigation.

Recall Information

On Nov. 5, 2010, Bravo Farms voluntarily recalled all Dutch Style Gouda cheese because it may be contaminated with E. coli 0157:H7. The product was distributed primarily through Costco in Southern California, Nevada, Arizona, Utah, Colorado, and New Mexico in 1.5 lb. pieces. It was also distributed through various retail stores within California in 8 oz. pieces.

An unopened (intact) package of Mauri Gorgonzola cheese tested as part of this ongoing investigation identified E. coli O157:H7 that does not match the outbreak strain. This cheese was cut, packaged and distributed by DPI Specialty Foods. On November 10, DPI Specialty Foods voluntarily recalled and warned consumers not to eat Mauri Gorgonzola cheese with sell-by dates of 01/13/11 and 01/14/11. On Friday, November 12, DPI Specialty Foods expanded this recall to include all cheese with sell by dates from 1/2/11 to 1/27/11. The strain of E. coli O157:H7 identified in the gorgonzola cheese is rare and no human illnesses with this strain have been observed in the PulseNet database for several years.

Clinical Features/Signs and Symptoms

Most people infected with E. coli O157:H7 develop diarrhea (often bloody) and abdominal cramps 2-8 days (3-4 days, on average) after swallowing the organism, but some illnesses last longer and are more severe. Infection is usually diagnosed by stool sample culture. While most people recover within a week, some develop a severe infection. A type of kidney failure called hemolytic uremic syndrome (HUS) can begin as the diarrhea is improving; this can occur among persons of any age but is most common in children under 5 years old and the elderly. Signs and symptoms of HUS may include: fever, abdominal pain, pale skin tone, fatigue and irritability, small, unexplained bruises or bleeding from the nose and mouth, decreased urination and swelling of the face, hands, feet, or entire body. Persons who experience these symptoms and believe they are at risk for HUS should seek emergency medical care immediately.

Advice to Consumers

Based on current information, there is a link with the consumption of one of several cheeses offered for sampling and sale at the “cheese road show” that was held at Costco Warehouses between October 5 and November 1 in Arizona, California, Colorado, New Mexico and Nevada. This cheese is Bravo Farms Dutch Style Gouda Cheese (Costco Item 40654), manufactured by Bravo Farms of Traver, CA.

Consumers who have any of this cheese should not eat it. Instead, they should return the cheese to the place of purchase or dispose of it in a closed plastic bag placed in a sealed trash can. This will prevent people or animals, including wild animals, from eating it.

CDC's Role in Food Safety

CDC leads federal efforts to gather data on foodborne illnesses, investigate foodborne illnesses and outbreaks, and monitor the effectiveness of prevention and control efforts. CDC is not a food safety regulatory agency but works closely with the food safety regulatory agencies, in particular, with FDA and FSIS.  CDC also plays a key role in building state and local health department epidemiology, laboratory, and environmental health capacity to support foodborne disease surveillance and outbreak response. Notably, CDC data can be used to help document the effectiveness of regulatory interventions.

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