Antibacterial Activity and Mechanism of Rose Essential Oil against Aeromonas veronii isolated from Northern snakehead (Channa argus).

Aims: To investigate and identify the antibacterial action and mechanism of rose essential oil (REO) against Aeromonas veronii isolated from northern snakehead for the first time by the phenotypic and metabolic analysis.

Methods and results: The two-fold broth microdilution and spread-plate method identified that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of REO against A. veronii were 1.25 μL mL-1 and REO impaired the growth in a concentration-dependent manner, indicating that REO possessed a significant bacteriostatic activity. Electron microscopy and live-dead cell staining found that REO caused a severe disruption of cellular morphology and increased the membrane permeability. Additionally, REO treatment induced the leakage of intracellular biomolecules such as proteins and nucleic acids from the bacteria. Metabolomics analysis showed that compared with the control, the REO treatment group exhibited a total of 190 differential metabolites (118 down-regulated and 72 up-regulated), which involved in the main metabolic pathways such as biotin metabolism, arginine biosynthesis, glutathione metabolism, lysine degradation, and histidine metabolism and the TCA cycle. These results verified that REO disturbed the metabolic processes of A. veronii to achieve the bacteriostatic effect.

Conclusion: The REO exhibited the effective antibacterial activity against A. veronii via breaking the cellular structure, increasing the membrane permeation and disrupting the metabolic processes.