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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #398714

Research Project: Analysis of Genetic Factors that Increase Foodborne Pathogen Fitness, Virulence, and Antimicrobial Resistance Transfer, to Identify Interventions against Salmonella and Campylobacter in Food Animals

Location: Food Safety and Enteric Pathogens Research

Title: Comparison of multi-drug resistant Salmonella enterica serovar Heidelberg outbreak isolates linked to dairy beef calves

item BURCIAGA, SELMA - Oak Ridge Institute For Science And Education (ORISE)
item Trachsel, Julian
item SOCKETT, DONALD - University Of Wisconsin
item AULIK, NICOLE - University Of Wisconsin
item Bearson, Shawn

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/23/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Over the last decade, six multistate outbreaks caused by Salmonella enterica serovar Heidelberg (S. Heidelberg) have occurred in the United States, primarily associated with poultry-related products. However, the latest multi-drug resistant (MDR) S. Heidelberg outbreak was linked to contact with dairy beef calves. Traceback investigation revealed calves infected with outbreak strains of S. Heidelberg showed symptoms of disease frequently followed by death from septicemia. Two variants were identified in this outbreak, one of which was dominant and more highly pathogenic. The aim of our study was to investigate the emergence of S. Heidelberg as a pathogen in bovine through characterization of selected bovine-origin outbreak isolates. Methods: For genomic comparison via pan-genome and SNP analyses, whole-genome sequencing was performed on two bovine-origin S. Heidelberg isolates with distinct PFGE patterns received at the Wisconsin Veterinary Diagnostic Laboratory at the University of Wisconsin-Madison during the 2015 to 2017 multistate outbreak. RNA-sequencing was performed to determine differentially expressed genes (DEGs) and predict their functional consequences, and invasion assays were performed with the HEp-2 cell line to assess pathogenicity. Results: Percent invasion of isolate SX 245 (JF6X01.0523) was 2-fold greater than SX 244 (JF6X01.0590). Genomic comparison revealed SX 245 lacked over 200 genes present in SX 244, including genes associated with Inc1 plasmid and phages, whereas genes related to multidrug transporter MdfA and IS1110 transposase were absent in SX 244. Thirty-five common genes, primarily fimbriae-related, displayed higher expression in SX 245. Conclusion: Fimbriae-related genes and unique mobile genetic elements may play a role in the increased pathogenicity and host range expansion of the S. Heidelberg isolates involved in the bovine-related outbreak.