Abstract
This study investigated the synergistic antibacterial mechanism of ginger essential oil (GEO) and rosemary essential oil (REO) against Shewanella putrefaciens. Antibacterial efficacy and interactions were assessed by determining the minimum inhibitory concentration (MIC), fractional inhibitory concentration (FIC) index, and growth curves. Membrane integrity was evaluated using confocal laser scanning microscopy (CLSM), leakage of intracellular components, and alkaline phosphatase (AKPase) activity. Structural damage was observed via scanning electron microscopy (SEM). The effects on antioxidant defense and energy metabolism were analyzed by measuring superoxide dismutase (SOD), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) activities. Biofilm inhibition capacity was also examined. Results demonstrated a synergistic effect (FIC index = 0.375). The combination of GEO and REO caused severe membrane damage, intracellular leakage, inhibition of key enzyme activities, and effective biofilm inhibition. The synergistic mechanism involves membrane disruption, suppression of metabolic pathways, and biofilm inhibition.