Chicken Salmonella outbreak persists, sickens 51 more

Chicken wings
Chicken wings

Levent Konuk / iStockphotos

A chicken-related Salmonella outbreak that health officials thought had gone away has come back to haunt consumers again, affecting 51 more people in the past month and a half, the Centers for Disease Control and Prevention (CDC) announced today.

The year-old outbreak, with Foster Farms brand chicken as the likely source, has expanded to 481 cases in 25 states and Puerto Rico, the CDC said today. That's up from 430 cases on Jan 16.

New cases were reported in Arizona, 3; California, 44; Hawaii, 1; Tennessee, 1; and Utah, 2. Tennessee and Hawaii had not been affect ted by the outbreak previously.

The cases involve seven strains of Salmonella Heidelberg that are resistant to several commonly prescribed antibiotics, the CDC said.

The number of reported infections involving the seven strains returned to baseline levels in January, leading the CDC to believe the outbreak was over. But surveillance in February indicated that infections from two of the previously rare outbreak strains have again exceeded the number expected to be reported.

On the basis of information from 472 cases, onset dates in the outbreak ranged from Mar 1, 2013, to Feb 11, 2014, the CDC reported. Of 394 people with available information, 151 (38%) were hospitalized. Thirteen percent of the patients have suffered blood infections, which is well above the 5% level typical for Salmonella cases.

As noted in previous CDC updates, the vast majority of patients are from California. The percentage from that state climbed slightly since the previous update, from 74% to 76%.

Evidence in retail chicken

Through the National Antimicrobial Resistance Monitoring System (NARMS), one of the two outbreak strains that increased was found in a retail sample of Foster Farms chicken that was bought Jan 27 in California, the CDC reported.

The US Department of Agriculture (USDA) found the other outbreak strain in a leftover sample of raw chicken from a sick person's home in California, the statement said. Using shopper card records (in the absence of packaging), investigators determined that the chicken was probably produced by Foster Farms. The Salmonella strain isolated from the person, however, differed from the one found in the leftover sample.

The USDA announced in October that it was allowing three Foster Farms facilities linked to the outbreak to continue operating after they made changes in their slaughter and processing methods. One of the plants, however, was temporarily closed by the USDA on Jan 8 because of cockroaches and other "egregious insanitary conditions."

The CDC noted that the antibiotics to which the outbreak strains are resistant are not typically used to treat Salmonella bloodstream infections or other severe Salmonella cases, but resistance can increase the risk of hospitalization.

See also:

Mar 4 CDC statement

Related Jan 17 CIDRAP News item


CDC map: Persons infected with the outbreak strain of Salmonella Heidelberg, by State*

*n=481 for whom information was reported as of Feb 28, 2014.

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