Salmonella outbreakDrug-resistant Salmonella outbreak in seven states

The Centers for Disease Control and Prevention (CDC) said it was collaborating with public health and agriculture officials in many states and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) to investigate a multistate outbreak of Salmonella Heidelberg infections. Public health investigators are using DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They are using data from PulseNet, 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.

Seven strains of Salmonella Heidelberg bacteria have been identified as being linked to this outbreak. Four of these strains are rarely reported to PulseNet. The other three strains are more common, with several ill persons infected with each strain reported to CDC monthly. The DNA fingerprints of the Salmonella Heidelberg bacteria associated with the current outbreak include the strain that was also associated with a multistate outbreak of Salmonella Heidelberg linked to Foster Farms brand chicken during 2012-13.

The outbreak strains of Salmonella Heidelberg are resistant to several commonly prescribed antibiotics. This antibiotic resistance may be associated with an increased risk of hospitalization or possible treatment failure in infected individuals.

CDC says that as of 7 October 2013, a total of 278 individuals infected with the outbreak strains of Salmonella Heidelberg have been reported from seventeen states. Most of the ill persons (77percent) have been reported from California. The number of ill persons identified in each state is as follows: Alaska (2), Arkansas (1), Arizona (11), California (213), Colorado (4), Connecticut (1), Florida (1), Hawaii (1), Idaho (2), Michigan (2), North Carolina (1), Nevada (8), Oregon (8), Texas (5), Utah (2), Washington (15), and Wisconsin (1).

Among 274 persons for whom information is available, illness onset dates range from 1 March to 24 September 2013. Ill persons range in age from <1 year to 93 years, with a median age of 20 years. Fifty-one percent of ill persons are male. Among 183 persons with available information, 76 (42 percent) reported being hospitalized. No deaths have been reported.

The outbreak can be visually described with a chart showing the number of people who became ill each day or week. This chart is called an epi curve. Illnesses that occurred after 1 September 2013 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of two to three weeks. See more details in SalmonellaOutbreak Investigations: Timeline for Reporting Cases.

Foster Farms has issued a statement saying it was cooperating with CDC and other federal and state health officials.

NPR reports that news of the outbreak has received a lot of attention because it comes during the federal government shutdown. There is a fear that no one is on the job at a critical time. USDA says, however, that its work has not been slowed down since its inspectors and investigators have stayed on the job.

As NPR has reported, the CDC unit that tracks outbreaks has been working with less than half its normal staff. To help handle the current outbreak, the agency told NPR it has called back about thirty furloughed workers, including ten who work in the foodborne division.

“This is the kind of thing that you’ve got to get information into consumers’ hands,” Caroline Smith DeWaal, food safety director for the Center for Science and Public Interest, told NPR.

She says that since the communications staffs of both CDC and USDA are working at reduced capacity, it is a concern. “The agency’s ability to push out the information is a lot more limited than it would be otherwise.”