Supplementary Material to the Publication: Clonal relation between Salmonella enterica subspecies enterica serovar Dublin strains of bovine and food origin in Germany

OHEJP Project: BeOne

Salmonella enterica serovar Dublin (S. Dublin) is a host-adapted serovar that causes enteritis and/or systemic diseases in cattle. Because the serovar is not host-specific, it can infect other species, including human beings, causing severe disease and a higher mortality rate than other non-typhoidal serovars. Given that human illnesses are primarily caused by contaminated milk, milk products, and beef, data on the genetic connection between S. Dublin strains from livestock and food should be analyzed. 

Whole genome sequencing (WGS) was performed on 144 S. Dublin strains from cattle and 30 strains from food. Multilocus sequence typing (MLST) found that the majority of livestock and food isolates were of the sequence type ST-10. As discovered by core-genome Single-Nucleotide Polymorphisms Typing and core-genome MLST, 14 of 30 strains from food origin were clonally related to at least one strain from cattle. Without outliers, the remaining 16 food-borne strains fit into the genomic structure of S. Dublin in Germany. WGS demonstrated to be an effective method not only for learning about the epidemiology of Salmonella strains, but also for detecting clonal relationships between organisms isolated at different stages of production. This study discovered a strong genetic link between S. Dublin strains from cattle and food, and thus the potential to cause human infections. S. Dublin strains from both origins have a nearly comparable collection of virulence factors, emphasizing their ability to produce severe clinical symptoms in animals as well as humans, emphasizing the importance of effective S. Dublin management in a farm to fork strategy.