Ellen Araújo Malveira¹, Maria Kelva do Carmo¹, Paula Victória Soares¹, Mayron Alves de Vasconcelos², Edson Holanda Teixeira¹

Staphylococcus epidermidis is a Gram-positive bacterium that is a commensal of human skin, playing an important role in maintaining skin homeostasis, promoting wound healing, and preventing pathogen colonization. However, it is also one of the most frequent causes of implant associated infections and biofilm formation, which has led to increasing interest in developing new therapeutic strategies targeting S. epidermidis, particularly its biofilms. In this context, bioactive compounds derived from native Brazilian plants have gained attention for their potential in contributing to novel treatment approaches. This study aimed to evaluate the effect of oleoresin extracted from Copaifera pubiflora on mature S. epidermidis biofilms. Two strains of S. epidermidis were used: ATCC 12228, characterized as a weak biofilm producer, and ATCC 35984, known for its strong biofilm formation and methicillin resistance. Bacterial cultures were grown in flat bottom 96-well polystyrene plates and incubated for 24 hours, followed by exposure to oleoresin at concentrations ranging from 1000 to 15.625 µg/mL. After 24 hours of treatment, assays were conducted to quantify biofilm biomass using crystal violet staining and to determine the number of viable cells within the biofilms. Biomass quantification revealed complete biofilm reduction at all tested concentrations for S. epidermidis ATCC 12228. For S. epidermidis ATCC 35984, approximately 90% biomass reduction was observed. Regarding the viability of S. epidermidis ATCC 12228 biofilms, a decrease in colony forming units (CFUs) ranging from approximately 1.6 to 0.6 log units was observed compared to untreated controls. In contrast, no significant reduction in viability was detected for the ATCC 35984 strain, except at 125 µg/mL, which led to a modest decrease of around 0.2 log units. These findings may be attributed to the differing biofilm forming capacities of the strains. The activity of C. pubiflora oleoresin against mature S. epidermidis biofilms, including a methicillin-resistant strain, highlights its potential as an antibiofilm agent and its possible role in the development of novel antimicrobial therapies.

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