Ovine mastitis is a significant welfare and financial issue in dairy sheep flocks. In milking ewes, the main causative agent of clinical mastitis is Staphylococcus aureus and of subclinical mastitis coagulase-negative staphylococci. Biofilm production is a virulence factor of these bacteria, which contributes to their increased pathogenicity. Objective of the present study was to evaluate under field conditions the efficacy of a novel vaccine, which induces antibodies against the poly-N-acetyl β-1,6 glucosamine exopolysaccharide (PNAG), the main component of the extracellular biofilm matrix of Staphylococcus. Consequently, vaccination avoids biofilm formation by these organisms.

Efficacy of a novel vaccine active against biofilm formaiton by staphylococci in protecting ewes from staphylococcal mastitis. The effect was stronger during the initial stage of the lactation period, when incidence risk of mastitis is increased, due to the post-partum reduced immunity often observed in ewes.