Baicalin Represses Type Three Secretion System of through PQS System.

Therapeutics that target the virulence of pathogens rather than their viability offer a promising alternative for treating infectious diseases and circumventing antibiotic resistance. In this study, we searched for anti-virulence compounds against from Chinese herbs and investigated baicalin from as such an active anti-virulence compound. The effect of baicalin on a range of important virulence factors in was assessed using -based reporters and by phenotypical assays. The molecular mechanism of the virulence inhibition by baicalin was investigated using genetic approaches. The impact of baicalin on pathogenicity was evaluated by both in vitro assays and in vivo animal models. The results show that baicalin diminished a plenty of important virulence factors in , including the Type III secretion system (T3SS). Baicalin treatment reduced the cellular toxicity of on the mammalian cells and attenuated in vivo pathogenicity in a infection model. In a rat pulmonary infection model, baicalin significantly reduced the severity of lung pathology and accelerated lung bacterial clearance. The PqsR of the quinolone signal (PQS) system was found to be required for baicalin's impact on T3SS. These findings indicate that baicalin is a promising therapeutic candidate for treating infections.