Identification of lactoferrin-binding proteins inStreptococcus dysgalactiaesubsp.dysgalactiaeandStreptococcus agalactiaeisolated from cows with mastitis

Three strains of Streptococcus dysgalactiae subsp. dysgalactiae (S. dysgalactiae) and five strains of Streptococcus agalactiae were used to identify lactoferrin-binding proteins (LBPs). LBPs from extracted surface proteins were detected by polyacrylamide gel electrophoresis and Western blotting. All strains of S. dysgalactiae evaluated had 52- and 74-kDa protein bands. All strains of S. agalactiae evaluated had 52-, 70- and 110-kDa protein bands. In addition, a 45-kDa band was detected in two of five S. agalactiae strains evaluated. This study demonstrated that S. dysgalactiae and S. agalactiae of bovine origin contain two and three major LBPs, respectively.