Aeromonas hydrophila is a pathogenic bacterium that can cause serious
infections both in humans and aquatic animals.
Antibiotics are the main approach for fighting against the pathogen. However, the emergence of antibiotic resistance has resulted in treatment failure. Therefore, drugs with novel strategies need to be developed. Quorum sensing has been recognized as a promising method for identifying anti-virulence drugs against
bacterial infections. The aim of this study was to identify novel drugs targeting quorum sensing of A. hydrophila as alternatives of
antibiotics in aquaculture. Thus, hemolytic activity, biofilm formation, qPCR and experimental
therapeutics assays were conducted. The results showed that
sanguinarine inhibited the growth of A. hydrophila at concentrations higher than 16 μg/mL, but the production of
aerolysin and biofilm formation was significantly inhibited at sub-inhibitory concentrations by disrupting the quorum sensing system. Cell viability results showed that
sanguinarine could provide protection for A549 cells from
aerolysin-induced cell injury. In addition, the mortality of channel catfish administered with
sanguinarine at a dosage of 20 mg/kg decreased to 40%, which showed a significant decrease compared with fish in positive group. Taken together, these findings demonstrated that anti-virulence strategies can be a powerful weapon for fighting against bacterial pathogens and
sanguinarine appears to be a promising candidate in the treatment of A. hydrophila
infections.