A Global Comparative Genomic Analysis of Major Bacterial Pathogens in Bovine Mastitis and Lameness.

Simple Summary: Dairy cows commonly suffer from two major health problems, mastitis (udder inflammation) and lameness (difficulty walking), which cause significant pain and reduce milk production. These conditions are mainly caused by bacteria; however we do not fully understand how these bacteria adapt and spread. In our work, we focused on the genetic material of four important bacterial species that cause the mentioned diseases, analyzing over 4300 bacterial samples worldwide. We found that these bacteria showed different genomic diversity patterns depending on where they originated, suggesting they adapt to local conditions. Some bacteria also showed signs of becoming resistant to common treatments, which is concerning for animal health. We found that two bacterial species, Escherichia coli and Staphylococcus aureus, were much more common and varied than the others. These findings help farmers and veterinarians better understand how these diseases spread and develop. This knowledge can lead to better treatments and prevention strategies, ultimately improving cow welfare and dairy farm productivity while reducing economic losses in the dairy industry. This study presents a comprehensive genomic reanalysis of major bacterial pathogens causing bovine mastitis and lameness, focusing on Staphylococcus aureus, Escherichia coli, Fusobacterium necrophorum, and Treponema phagedenis. Through our analysis of 4326 bacterial genomes from global databases, we identified distinct patterns in genomic diversity, virulence factors and antimicrobial resistance genes across these species. E. coli showed the highest genomic diversity with 3779 isolates, of which 98% exhibited high-quality genome sequences. Similarly, S. aureus demonstrated significant genomic plasticity across 524 isolates, with 99.8% classified as high-quality genomes. Geographical analysis revealed distinct regional variations in strain distribution, with North America contributing 45.3% of all isolates, followed by Asia (21.2%) and Europe (18.1%). Furthermore, we identified novel virulence mechanisms and resistance patterns specific to each pathogen, with particular emphasis on the evolution of antimicrobial resistance genes. Our findings provide crucial insights into pathogen adaptation and host–microbe interactions, suggesting the need for region-specific intervention strategies. These results have significant implications for developing targeted therapeutic approaches and improving bovine health management practices. [ABSTRACT FROM AUTHOR]