Sanguinarine Protects Channel Catfish against Aeromonas hydrophila Infection by Inhibiting Aerolysin and Biofilm Formation.

Lushan Zhang,Qiuhong Yang,Liang Ma,Jing Dong,Xiaohui Ai,Yongtao Liu

doi:10.3390/pathogens11030323

Lushan Zhang, Qiuhong Yang + Show 4 more

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https://doi.org/10.3390/pathogens11030323

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Abstract

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.

Highlights

Aeromonas hydrophila (A. hydrophila) is a bacterium, widely distributed in aquatic environments, which can cause a wide range of infectious diseases in aquatic animals
The findings indicated that the emergence of antibiotic resistance limited the application of antibiotics in treating bacterial infections in aquaculture
Wang et al investigated the inhibitory effects of sanguinarine against Saprolegnia sp. spores and mycelium, and the results showed that sanguinarine could provide an inhibition against both spores and mycelium, indicating that sanguinarine could be chosen as a potential fishery drug against Saprolegnia sp. infections [38]

Summary

Introduction

Aeromonas hydrophila (A. hydrophila) is a bacterium, widely distributed in aquatic environments, which can cause a wide range of infectious diseases in aquatic animals. Pathogenic A. hydrophila is the main cause of bacterial infections in freshwater fisheries in China. A. hydrophila-associated infections have brought huge economic losses in aquaculture, and have seriously restricted the sustainable and healthy development of the industry [1]. A. hydrophila has become a zoonotic bacterial pathogen because it can transmit from diseased fish, polluted water and under-cooked seafood to humans by consumption routes [2]. Antibiotics are the main strategy in the fight against bacterial infections in both human and animals [3]. The abuse of antibiotics results in the emergence of bacterial resistance [4]. Drugs with novel targets are urgently needed

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