Baicalein Ameliorates Streptococcus suis-Induced Infection In Vitro and In Vivo

Lu, Hao; Li, Xiaodan; Wang, Gaoyan; Wang, Chenchen; Feng, Jiajia; Lu, Wenjia; Wang, Xiangru; Chen, Huanchun; Liu, Manli; Tan, Chen

As an important zoonotic pathogen, Streptococcus suis (S. suis) infection has been reported to be a causative agent for variety of diseases in humans and animals, especially Streptococcal toxic shock-like syndrome (STSLS), which is commonly seen in cases of severe S. suis infection. STSLS is often accompanied by excessive production of inflammatory cytokines, which is the main cause of death. This calls for development of new strategies to avert the damage caused by STSLS. In this study, we found for the first time that Baicalein, combined with ampicillin, effectively improved severe S. suis infection. Further experiments demonstrated that baicalein significantly inhibited the hemolytic activity of SLY by directly binding to SLY and destroying its secondary structure. Cell-based assays revealed that Baicalein did not exert toxic effects and conferred protection in S. suis-infected cells. Interestingly, compared with ampicillin alone, Baicalein combined with ampicillin resulted in a higher survival rate in mice severely infected with S. suis. At the same time, we found that baicalein can be combined with meropenem against MRSA. In conclusion, these results indicate that baicalein has a good application prospect.