Ginkgolide B drives TCA cycle to accelerate Streptococcus suis biofilm dissociation.

Streptococcus suis (S. suis) is an important zoonotic pathogen that often forms biofilm, leading to persistent clinical infections and exacerbation of antibiotic resistance. There is an urgent need to develop novel antibiofilm strategies. In this study, for the first time, lactate dehydrogenase (LDH) was targeted with the aim of reactivating the metabolic activity of bacteria embedded in biofilm using natural product molecules, thereby disrupting mature biofilm. Through virtual screening based on the TCMSP database, molecular docking, and molecular dynamics simulations, two potential molecules, ginkgolide B and daidzein were identified. The results showed that ginkgolide B significantly eradicated mature biofilm of S. suis at 160 µg/mL, whereas daidzein did not exhibit such an effect. Ginkgolide B treatment led to a marked accumulation of tricarboxylic acid (TCA) cycle intermediates (pyruvate, malate, fumarate, and isocitrate), a substantial downregulation of the pentose phosphate pathway product ribose-5-phosphate, and a global upregulation of NADH as well as various high energy phosphate compounds and amino acids. These findings suggest that ginkgolide B may interfere with TCA cycle, leading to reduced lactate fermentation, enhanced accumulation of TCA cycle-related metabolites, and broader metabolic changes in biofilm-associated S. suis. This metabolic disturbance may contribute to the disruption of mature biofilm. This study validates the feasibility of a 'metabolic activation' strategy in eradicating mature biofilm of S. suis and provides ginkgolide B as a candidate molecule for the development of novel antibiofilm agents.