CDC finds E coli outbreak strain in cheese

Nov 11, 2010 (CIDRAP News) – Lab studies have found Escherichia coli O157:H7 in Gouda cheese implicated in a five-state outbreak that has sickened eight more people, the US Centers for Disease Control and Prevention (CDC) said yesterday.

E coli matching the outbreak strain was found in samples from two opened packages from two different patients' homes, and preliminary tests from an unopened package from a Costco store were positive for E coli O157:H7, the CDC said. Also, tests on samples from opened packages from two more patients revealed E coli O157:H7, and more tests are under way to confirm the findings.

On Nov 4 federal officials and Costco stores warned customers not to eat a raw milk Gouda cheese made by Bravo Farms, based in Traver, Calif., after the CDC received reports of 25 illnesses in five states that had links to the product. The case count in the outbreak has now reached 33, including 15 in Arizona, 10 in Colorado, 3 each in California and New Mexico, and 2 in Nevada, the CDC reported.

The CDC said 15 of the patients were hospitalized, including one with hemolytic uremic syndrome, a potentially fatal kidney complication. Patients range in age from 1 to 81, with Oct 24 as the latest illness onset date. No deaths have been reported.

The outbreak involves a rare strain of E coli O157:H7 that the CDC has never seen before in its PulseNet database, a national pathogen-subtyping network.

Federal investigators are testing more food samples, conducting traceback studies, and exploring the distribution chain to see where contamination could have occurred. The CDC said Costco is assisting with the investigation.

In a statement issued shortly after the initial recall, Bravo Farms said it was taking the outbreak seriously and expressed condolences to the sickened patients. "We are working to be certain our cheeses are completely safe, and to identify the cause of this tragedy," the company said.

In other food safety developments related to cheese, the US Food and Drug Administration (FDA) yesterday said a Colorado company has recalled one lot of its Mauri Gorgonzola cheese after tests found E coli O157:H7. DPI Specialty Foods in Tualatin, Ore., cut, packaged, and distributed the Gorgonzola to Costco stores in Colorado.

The FDA said Colorado lab officials found the positive Gorgonzola sample while they were investigating the Gouda E coli outbreak.

The FDA said so far no illnesses have been linked to the cheese and that the E coli found in the Gorgonzola is different from the strain involved in the Gouda-related outbreak. Investigators are trying to determine how the cheese became contaminated and if any illnesses are linked to it, according to the FDA statement.

See also:

Nov 10 CDC outbreak update

Nov 5 CIDRAP News story "Costco Gouda suspected in 5-state E coli outbreak"

Nov 10 FDA recall notice

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