CDC and public health officials in several states investigated an outbreak of Salmonella infections with serotypes of Enteritidis, Hadar, Indiana, Infantis, Mbandaka, and Muenchen.

Epidemiologic and laboratory data showed that contact with backyard poultry made people sick.

A total of 1,135 people infected with one of the outbreak strains were reported from 48 states, the District of Columbia, and Puerto Rico. Illnesses started on dates ranging from December 15, 2020 to October 10, 2021. Of 829 people with information available, 273 (33%) were hospitalized. Two deaths were reported.

Cases reported purchasing backyard poultry from multiple locations including feedstores, auctions and directly from hatcheries. Traceback of these purchases did not identify a single, common source of backyard poultry.

WGS was used to identify any predicted antibiotic resistance for bacteria from 1,101 sick people’s samples, 4 animal samples, and 7 environmental samples. Of the 1,112 samples, 394 (35%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.5%), ampicillin (0.9%), chloramphenicol (0.3%), cefoxitin (0.5%), ceftriaxone (0.5%), ciprofloxacin (0.1%), gentamicin (1.8%), kanamycin (0.4%), streptomycin (33.8%), sulfamethoxazole (2.2%), tetracycline (32.6%), and trimethoprim-sulfamethoxazole (0.2%).

The outbreak was declared over on November 18, 2021.