Local, state and federal public health officials investigated an outbreak of Salmonella Newport infections with illness onset dates ranging from October 1, 2016 to July 19, 2017. A total of 106 cases were identified in 21 states. Among 88 (83%) patients with known outcomes, 42 (48%) were hospitalized and one died.

Epidemiologic and laboratory evidence indicated that contaminated ground beef was the likely source of this protracted outbreak. A significantly higher percentage of patients than expected ate ground beef at home, and a patient's leftover ground beef yielded the outbreak strain. Dairy cows colonized or infected with the outbreak strain before slaughter were hypothesized to be the source of the outbreak.

This investigation identified the outbreak strain only in samples from dairy cows in New Mexico. All four isolates from dairy cattle samples were closely related by WGS to isolates from patients.