A multistate outbreak of Salmonella Anatum infections was detected in the US in June 2016.
It involved 32 patients from nine states with illness onset dates from May 6 to July 9, 2016.
Investigational evidence indicated that fresh hot peppers were the likely source of the outbreak.
In summer 2016, local and state health departments, CDC, and the Food and Drug Administration investigated an outbreak of Salmonella Anatum infections with an indistinguishable pulsed-field gel electrophoresis (PFGE) pattern.
Whole-genome sequencing (WGS) was performed to further characterize clinical isolates and an Anaheim pepper isolate with the same PFGE pattern from April 2016.
The strong genetic relationship between the clinical and food isolates, in combination with the epidemiologic and traceback evidence, indicated that fresh hot peppers were the likely source of the outbreak.
However, a pepper type or source farm could not be identified.
This outbreak highlights challenges in reconciling epidemiologic and WGS data, the difficulties of identifying ingredient-level exposures by epidemiologic investigations alone, and the complexity of the hot-pepper supply chain.