Investigation Details

April 30, 2019

CDC, the U.S. Department of Agriculture’s Food Safety Inspection Service (USDA-FSIS), and public health and regulatory officials in several states investigated a multistate outbreak of Salmonella Reading infections linked to raw turkey products.

Public health investigators used the PulseNet system to identify illnesses that may have been part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting was performed on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS gives a more detailed DNA fingerprint than PFGE. WGS performed on Salmonella from ill people in this outbreak showed that they are closely related genetically. This means that the ill people were more likely to share a common source of infection.

As of April 22, 2019, a total of 358 people infected with the outbreak strain of Salmonella Reading were reported from 42 states and the District of Columbia. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Illnesses started on dates from November 20, 2017, to March 31, 2019 . Ill people ranged in age from less than 1 year to 101, with a median age of 42. Forty-eight percent of ill people were female. Of 302 people with information available, 133 (44%) were hospitalized. One death was reported from California.

Predicted antibiotic resistance based on whole genome sequencing (WGS) was determined for 487 isolates. There was no antibiotic resistance predicted for 173 (36%) isolates from 86 ill people and 87 food, animal, and environmental samples. The remaining 314 isolates (180 from ill people and 134 from food, animal, and environmental samples) contained genes for resistance or decreased susceptibility to some or all of the following antibiotics: ampicillin (52% of all 487 isolates), streptomycin (32%), sulfamethoxazole (31%), tetracycline (32%), kanamycin (3.4%), gentamicin (0.6%), nalidixic acid (0.4%), ciprofloxacin (0.4%), trimethoprim-sulfamethoxazole (0.4%), and fosfomycin (0.2%). Testing of 20 outbreak isolates using standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory confirmed these results (fosfomycin and kanamycin were not tested by this method). Most (99%) of the human infections in this outbreak were susceptible to the antibiotics that are commonly used for treatment when susceptibility results are not available. These results mean that this resistance likely will not affect the choice of antibiotics used for treatment.

Investigation of the Outbreak

State and local health departments interviewed ill people about the foods they ate and other exposures in the week before they became ill. Of the 200 ill people interviewed, 130 (65%) reported preparing or eating turkey products that were purchased raw, including ground turkey, turkey pieces, and whole turkeys. Ill people reported buying many different brands of raw turkey products from multiple stores. Also, 4 of the 200 ill people interviewed became sick after pets in their home ate raw ground turkey pet foodexternal icon. Five of the 200 ill people interviewed worked in a facility that raises or processes turkeys, or lived with someone who did. In February 2019, 47 people became ill after eating turkey that was not handled properly at an event in Iowa.

Public health officials in Arizona and Michigan collected unopened Jennie-O brand ground turkey from the homes of ill people. Officials in Minnesota also collected raw turkey pet food that was served to pets in ill people’s homes. The outbreak strain of Salmonella Reading was identified in samples of the ground turkey and the raw turkey pet food. WGS showed that Salmonella bacteria isolated from ill people, from ground turkey, and from raw turkey pet food were all closely related genetically. These results provided more evidence that people in this outbreak got sick from eating or handling turkey products.

Several Jennie-O brand ground turkey products were recalled in November and December 2018. Raws for Paws recalled raw turkey pet food in February 2018, and Woody’s Pet Food Deli recalled raw turkey pet food in January 2019.

The outbreak strain was also identified in samples from raw turkey products from 24 slaughter and 14 processing establishments. The samples collected by FSIS at these slaughter and processing establishments were part of FSIS’s routine testing under the Salmonella performance standards. Furthermore, WGS showed that the Salmonella strain isolated from these samples is closely related genetically to the Salmonella strain from ill people.

Available data indicate that this strain of Salmonella Reading is present in live turkeys and in raw turkey products. A single, common supplier of raw turkey products or of live turkeys was not identified that could account for the whole outbreak.

This is the final update for this outbreak investigation. The number of reported new illnesses has decreased, but people could continue to get sick. CDC continues to monitor the PulseNet database for illnesses and work with states to interview ill people. CDC’s National Antimicrobial Resistance Monitoring System (NARMS) continues to analyze Salmonella isolates for patterns of antibiotic resistance. CDC will provide updates in the future if there is an increase in newly reported cases.