Abstract

Staphylococcus aureus (S. aureus) is a major cause of bovine mastitis. In this present study, we assessed the efficacy of the recombinant A region of collagen adhesin (rCna-A) as a mastitis vaccine in a mouse model. Three groups of mice were immunized with either rCna-A, inactivated S. aureus, or phosphate-buffered saline (PBS) as a control. IgG and IgG subtype titers of mice in the rCna-A vaccine group were significantly higher than those in the killed vaccine group (P<0.01). Immunized lactating mice were challenged with S. aureus via the intramammary route. Significantly, fewer bacteria were recovered from mice in the rCna-A group than from those in the killed vaccine group (P<0.001). Histopathology indicated that the mammary structure showed greater integrity and a milder inflammatory response in the rCna-A group as compared with both the inactivated vaccine and PBS control groups. These results suggested that the rCna-A protein may be an attractive target for a vaccine against S. aureus-induced mastitis. 

Key words: Staphylococcus aureus, collagen adhesion, inactivated vaccine, mastitis.