In 2023, public health officials investigated an outbreak of salmonellosis associated with backyard poultry. As of June 15, 2023, 410 people infected with one of the outbreak strains had been reported from 45 states. Of the 282 people with hospitalization information available, 84 (30%) had been hospitalized. No one had died. Illnesses started on dates ranging from January 1, 2023 to May 25, 2023.

Multiple Salmonella serotypes were involved including Braenderup, Enteritidis, Indiana, Infantis, Mbandaka, and Typhimurium.

Investigators in Michigan, Minnesota, Utah, and Wisconsin collected samples from the areas where chicks were housed at stores that sell poultry or at sick people's homes. Whole genome sequencing (WGS) showed that Salmonella Braenderup, Enteritidis, Mbandaka, and Infantis from the animals' environment were closely related to bacteria from sick people. These poultry were supplied by four different poultry hatcheries.

WGS analysis was used to predict resistance to antibiotics for bacteria from 408 people’s samples and 16 environmental samples. Of the 424 total samples, 33 (8%) were predicted to be resistant to one or more of the following antibiotics: ampicillin, cefoxitin, ceftiofur, ceftriaxone, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole, tetracycline, and amoxicillin-clavulanic acid. Bacteria from the remaining 391 samples had no predicted resistance.