Genotypes and phenotypes of staphylococci on selected dairy farms in Vermont

The genus Staphylococcus contains at least 47 species and 23 subspecies. Bacteria in this genus are ubiquitous; many are commensals on human and animal skin and can be opportunistic pathogens. In dairy cattle, staphylococci are the leading cause of intramammary infections (IMI) and mastitis. Mastitis is the inflammation of the mammary gland, and is one of the leading infectious diseases causing production losses in the dairy industry. Staphylococcus species other than Staphylococcus aureus are referred to as non-aureus staphylococci (NAS). In the dairy industry, S. aureus is the most common mastitis causative agent and is considered a major mastitis pathogen compared to the NAS, which as a group have been described as minor mastitis pathogens. The NAS species are increasingly recognized as an important cause of bovine mastitis, although the relative role of some species is still uncertain. Our understanding of the local and global epidemiology of NAS mastitis is improving with application of more accurate DNA sequence-based species identification methods and techniques to discriminate between strains within species.


The major goals of this project, part of my PhD dissertation, were to describe Staphylococcus mastitis epidemiology, and to identify phenotypes that may contribute to persistence in various niches on selected dairy farms in Vermont. We conducted 2 field studies on 2 groups of farms in Vermont. In the first study, we collected S. aureus isolates from bulk tank milk of

Leave a Reply

%d bloggers like this: