Matrine inhibition the virulence of Streptococcus agalactiae by destroying Capsule and Biofilm formations

Streptococcus agalactiae is one of the main pathogens that induces mastitis in dairy farms in China. It usually causes clinical symptoms of mastitis and brings significant losses to the dairy farming industry. Matrine is a natural alkaloid isolated from roots and stems of the legume plant Sophora, which has the functions of anti-oxidation, Immunomodulation, affecting the expression of inflammatory factors, and regulating cell apoptosis. Under the background of banning antibiotics, matrine has broad prospects in animal husbandry production. Our results indicate that matrine inhibits the activity of Streptococcus agalactiae in the concentration-dependent manner. Furthermore, matrine can inhibit the adhesion and survival rate of Streptococcus agalactiae, reduce the production of capsular polysaccharides of Streptococcus agalactiae, and limit the formation of biofilms. Validated by transcriptomics and qRT-PCR, the results show that matrine reduces the immune escape and invasion ability of GBS by regulating the expression of GBS-related virulence genes. These results provide a promising strategy for prevention and antibiotic-free treatment of mastitis caused by streptococcus agalactiae.