Abstract:Blood-brain barrier (BBB), one of the natural structural and functional barriers of the central nervous system (CNS), can prevent the invasion of pathogenic bacteria. However, pathogenic bacteria can interact with brain endothelial cells via their virulence factors to induce host immune response and massive secretion of cytokines and chemokines and destroy tight junction proteins to penetrate the blood brain barrier, causing bacterial meningitis and irreversible nervous system damage. Streptococcus is a major pathogen causing bacterial meningitis. In recent years, significant progress has been achieved in the research on the molecular mechanism of Streptococcus penetrating the blood-brain barrier. This article reviews the progress in the mechanism of main Streptococcus species including Streptococcus pneumoniae, Streptococcus suis, group B Streptococcus, and Streptococcus equi in passing through the blood-brain barrier.