Streptococcus suis serotype 2 (SS2) has become a leading pathogen responsible for swine industry and human infections, causing enormous economic loss and triggering food safety risk. New and alternative strategies for combating this microorganism are urgently needed. Suilysin (SLY), a pore-forming toxins produced by SS2 has been revealed play critical role during its infection and could be an ideal target for combating this pathogen. Here, we found that formononetin (Form) inhibited the haemolytic activity of SLY without exerting growth pressure on SS2 or affecting the expression of SLY. At the cellular infection level, Form treatment diminished the cytotoxicity induced by SLY or SS2 and inflammatory response induced by SS2. In addition, the treatment with Form reduced bacterial burden in livers and spleens in SS2 infected mice. These data revealed that Form could attenuate the pathogenesis of SS2 both in vitro and in vivo by targeting SLY, suggesting that this compound could be used in combating S. suis infections.

猪链球菌血清型2（SS2）已成为负责养猪业和人类感染的主要病原体，造成了巨大的经济损失并引发了食品安全风险。迫切需要新的和替代的策略来对抗这种微生物。溶血素（SLY）是由SS2产生的一种形成孔的毒素，已被发现在其感染过程中起着至关重要的作用，并且可能是抵抗这种病原体的理想靶标。在这里，我们发现formononetin（Form）抑制了SLY的溶血活性，而没有对SS2施加生长压力或影响SLY的表达。在细胞感染水平，形式治疗降低了SLY或SS2诱导的细胞毒性和SS2诱导的炎症反应。另外，用Form处理可以减少SS2感染小鼠的肝脏和脾脏细菌负担。猪链球菌感染。