Genomic Evidence Supporting a One Health Perspective on Staphylococcus aureus Bovine Mastitis.

Area of Science:

• Microbiology
• Genomics
• Veterinary Medicine

Background:

• Staphylococcus aureus is a significant pathogen affecting both humans and animals, including dairy cows.
• Understanding its genetic diversity and host adaptation is crucial for public and animal health.

Purpose of the Study:

• To genetically characterize Staphylococcus aureus from bovine milk.
• To compare bovine isolates with human reference genomes for host adaptation and inter-species transmission insights.
• To analyze antimicrobial resistance profiles and mobile genetic elements.

Main Methods:

• Whole-genome sequencing and multi-locus sequence typing (MLST) of bovine S. aureus isolates.
• Comparative genomics with human-derived reference genomes.
• Assessment of antibiotic resistance genes and mobile genetic elements.

Main Results:

• Identified both bovine-adapted (CC97, CC133, CC151) and human-associated (CC1, CC5, CC8, CC30, CC45) S. aureus lineages.
• ST8 was the only shared sequence type between animal and human isolates, with distinct resistance profiles.
• Bovine strains showed loss of human virulence genes and acquisition of bovine-associated mobile genetic elements; animal isolates generally carried fewer resistance genes.

Conclusions:

• S. aureus exhibits significant genetic diversity and host-specific adaptations in both dairy cows and humans.
• Dynamic gene and mobile element content influences host association.
• Integrated One Health surveillance is essential for monitoring shared lineages and antibiotic resistance determinants.