Aqueous leaf extract from Eugenia dysenterica exhibits antimicrobial and antibiofilm activity against Staphylococcus aureus.

Staphylococcus aureus is a pathogen associated with various diseases, exhibiting biofilm ability and antimicrobial resistance. The search for new antimicrobial agents, especially natural ones, is crucial. This study evaluated the antibacterial and antibiofilm activities of the aqueous leaf extract from Eugenia dysenterica against S. aureus. Healthy leaves were dried, powdered and infused in water to obtain the extract. Reference strains S. aureus ATCC 25,923 and ATCC 29,213 were employed as model organisms. The minimum inhibitory concentration (MIC) was assessed using the microdilution technique in 96-well polystyrene microplates. The minimum bactericidal concentration (MBC) was evaluated by plating on standard count agar. Test surface assays were performed with polystyrene coupons, where the count of viable sessile cells (CVSC) was determined after sonication and agitation. Biofilm resistance was assessed after exposure to a chlorinated compound. The extract showed antimicrobial activity, with MICs values of 156-313 μg/mL and MBC values of 625-1,250 μg/mL. Antibiofilm activity was observed at inhibitory and subinhibitory concentrations. Even when CVSC was similar, the extract increased biofilm sensitivity to chlorinated compounds. The antimicrobial and antibiofilm potential of the aqueous leaf extract of E. dysenterica could aid S. aureus control in various fields, including the food and medical industries.