Selective adhesion of microorganisms to the ductular epithelium of the bovine mammary gland.

Streptococcus agalactiae, Streptococcus faecalis, Staphylococcus aureus, Escherichia coli, and Corynebacterium bovis were examined for their ability to adhere to the ductular epithelial cells of the bovine udder. S. agalactiae and S. aureus adhered readily and in large numbers, whereas the other organisms adhered poorly or not at all. The organisms showing the ability to adhere are those which frequently cause mastitis. These data suggest that selective adherence to the ductular epithelium may be the first stage in the pathogenesis of streptococcal and staphylococcal mastitis.