Induction of Anti‐Phagocytic Surface Properties of Staphylococcus aureus from Bovine Mastitis by Growth in Milk Whey

Abstract
Summary: The respiratory burst activity of bovine polymorphonuclear (PMN) cells in response to milk whey‐ and TSB‐grown S. aureus strains isolated from bovine mastitis was studied in whole blood chemiluminescence (CL) and in a CL system with purified bovine neutrophils. In both cases milk whey‐grown S. aureus strains elicited significantly less CL than homologous strains grown in TSB. Ingestion of milk whey‐grown S. aureus strains by bovine neutrophils was also considerably lower than that of the corresponding homologous organisms grown in TSB. Binding of complement factor C3 to serum‐opsonized milk whey‐grown S. aureus strains was lower compared with TSB‐grown homologous organisms. Moreover, 5 of 6 S. aureus strains grown in milk whey were significantly more resistant to in vivo clearance from the peritoneal cavity of mice compared with homologous bacteria grown in TSB.S. aureus strains grown in TSB exhibited hydrophobic surface properties, whereas homologous strains grown in milk whey were hydrophilic.