Bactericidal and anti-biofilm activity of ebastine against Staphylococcus aureus

Drug repurposing, offers promising opportunities to address infections caused by multidrug-resistant bacteria. This study was to evaluate the bactericidal activity, anti-biofilm properties, and potential mechanisms of the antihistamine drug ebastine against Staphylococcus aureus. The minimum inhibitory concentrations of ebastine against standard and clinical S. aureus isolates were determined using the broth microdilution method. The MIC values ranged from 2 to 8 µg·mL-1, indicating good activity against clinical drug-resistant strains. Time-kill curve analyses revealed a dose-dependent bactericidal effect. Regarding anti-biofilm activity, ebastine significantly inhibited biofilm formation at higher concentrations and demonstrated a moderate ability to eradicate preformed biofilms. Mechanistic studies revealed that ebastine exerted the antimicrobial effects by causing disruption to bacterial membrane integrity and inducing reactive oxygen species generation. Furthermore, safety evaluations showed that ebastine exhibited limited toxicity to mammalian cells, with negligible hemolytic effects and good overall safety profiles. This study provided new insights into the potential applications of ebastine in the field of antimicrobial therapy, highlighting its promise as a non-traditional antibacterial agent.