Applied antibacterial and surface decontamination potential of methyl salicylate-rich Gaultheria fragrantissima essential oil

AIMS: The persistence of biofilm-forming nosocomial pathogens on healthcare-associated surfaces represents a major challenge in infection control. This study aimed to evaluate the antibacterial, antibiofilm, membrane-disruptive, and surface decontamination potential of methyl salicylate-rich Gaultheria fragrantissima essential oil (GFEO) against clinically relevant pathogens. METHODS AND RESULTS: Antibacterial activity was determined by broth microdilution, while antibiofilm effects were assessed using crystal violet assays. Membrane-disruptive activity was evaluated by measuring cytoplasmic leakage, and synergistic interactions with antibiotics were analysed using checkerboard titration. Surface disinfection potential was examined using carrier-based assays on stainless steel, glass, and polystyrene surfaces. GFEO exhibited broad-spectrum antibacterial activity (MIC: 0.156-2.5 mg mL⁻¹) and significantly inhibited early-stage biofilm formation (69-92%). Rapid membrane permeabilization was observed within 10 min, with up to approx. 80% disruption at 2 × MIC after 60 min. Synergistic interactions were identified with selected antibiotics (FICI 0.25-0.5). In surface assays, GFEO achieved approximately 3 log₁₀ reductions for most strain-surface combinations within 20 min and up to 4.77 log₁₀ after 60 min. CONCLUSIONS: GFEO exhibits a potent membrane-mediated antimicrobial profile with strong antibiofilm and surface bactericidal activity, highlighting its potential as a natural agent for healthcare-associated infection control and environmental decontamination.