Genomic and Evolutionary Analysis of Two Salmonella enterica Serovar Kentucky Sequence Types Isolated from Bovine and Poultry Sources in North America

• Published in: PloS one 2016-10, Vol.11 (10), p.e0161225-e0161225
• Main Authors: Haley, Bradd J, Kim, Seon Woo, Pettengill, James, Luo, Yan, Karns, Jeffrey S, Van Kessel, Jo Ann S
• Format: Article
• Language: English
• Subjects: Agriculture; Animals; Biological Evolution; Biology and Life Sciences; Cattle - microbiology; Cattle Diseases - microbiology; Chickens; Chickens - microbiology; Cladistic analysis; Clinical isolates; Dairy cattle; Dairy farming; Dairy farms; Divergence; Drug Resistance, Bacterial - genetics; Evolution (Biology); Farms; Food; Food production; Food safety; Genes; Genetic polymorphisms; Genome, Bacterial - genetics; Genomes; Genomic analysis; Genomics; Laboratories; Medicine and Health Sciences; Microbial Sensitivity Tests; North America; Nutrition; People and places; Phylogeny; Plasmids - genetics; Polymorphism, Single Nucleotide - genetics; Poultry; Poultry Diseases - microbiology; Research and Analysis Methods; Salmonella; Salmonella enterica; Salmonella enterica - genetics; Salmonella Infections, Animal - genetics; Salmonella Infections, Animal - microbiology; Single-nucleotide polymorphism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0161225

Salmonella enterica subsp. enterica serovar Kentucky is frequently isolated from healthy poultry and dairy cows and is occasionally isolated from people with clinical disease. A genomic analysis of 119 isolates collected in the United States from dairy cows, ground beef, poultry and poultry products, and human clinical cases was conducted. Results of the analysis demonstrated that the majority of poultry and bovine-associated S. Kentucky were sequence type (ST) 152. Several bovine-associated (n = 3) and food product isolates (n = 3) collected from the United States and the majority of human clinical isolates were ST198, a sequence type that is frequently isolated from poultry and occasionally from human clinical cases in Northern Africa, Europe and Southeast Asia. A phylogenetic analysis indicated that both STs are more closely related to other Salmonella serovars than they are to each other. Additionally, there was strong evidence of an evolutionary divergence between the poultry-associated and bovine-associated ST152 isolates that was due to polymorphisms in four core genome genes. The ST198 isolates recovered from dairy farms in the United States were phylogenetically distinct from those collected from human clinical cases with 66 core genome SNPs differentiating the two groups, but more isolates are needed to determine the significance of this distinction. Identification of S. Kentucky ST198 from dairy animals in the United States suggests that the presence of this pathogen should be monitored in food-producing animals.