Case Study 9Tracking of a salmonellosis outbreak source using NGS (157)

Approximately 300 people from areas spanning 44 states and the District of Columbia became ill with salmonellosis stemming from ingestion of Salmonella enterica (S. enterica) serotype Montevideo. An epidemiologic investigation suggested that the cause of the outbreak was spiced salami produced at a New England processing facility. The manufacturer of the salami was also associated with a previous salmonellosis outbreak due to contaminated pistachios, but PFGE could not differentiate between the clinical Salmonella isolate from the spiced salami and the Salmonella that had originated from the pistachios. Therefore, the cause of the outbreak could have been ingredient supplies, the finished spiced salami product, or the pistachios. NGS was used to sequence 35 S. enterica sero-type Montevideo genomes collected from the previously mentioned sources. The source of the outbreak was a red and black pepper rub used in the production of the spiced salami.