Antimicrobial and Antibiofilm Activities of Abietic Acid against Skin-Associated Opportunistic Microorganisms

Skin infections caused by bacterial and fungal microorganisms pose significant global health challenges and are often exacerbated by biofilm formation and increasing antimicrobial resistance. This study investigated the antimicrobial and effects on biofilm biomass of abietic acid, isolated from pine rosin, against key skin-associated opportunistic microorganisms. The antimicrobial activity of abietic acid against <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, <i>Escherichia coli</i>, and <i>Candida albicans</i> was evaluated using disc diffusion, broth microdilution, and time-dependent growth inhibition assays. Abietic acid produced measurable growth inhibitory zones against all tested microorganisms and exhibited minimum inhibitory concentrations as low as 16 μg/ml. Time-dependent OD₆₀₀ measurements demonstrated concentration-dependent inhibition of microbial growth. In addition, abietic acid treatment resulted in a significant reduction in biofilm biomass across all tested microorganisms. These findings suggest that abietic acid exhibits antimicrobial activity and reduces biofilm biomass <i>in vitro</i> against clinically relevant opportunistic microorganisms and may warrant further investigation for potential applications related to skin and soft tissue infections.