Atividade antibacteriana, sinérgica e antibiofilme de extrato etanólico de Mimosa tenuiflora (Fabaceae) frente a Staphyloccocus aureus de leite bovino

Abstract

Staphylococcus spp. with ability to form biofilms are increasingly known to cause persistent intramammary infections and the search for alternatives to inhibit the development of biofilms is critical, especially when using plants with therapeutic potential. The objective of this study was to evaluate the antimicrobial, synergistic and antibiofilm effect of the crude ethanolic extract of Mimosa tenuiflora (CEEMT) against Staphylococcus aureus biofilm producers, in addition to verify the presence of efflux pump as mechanism of resistance of these bacteria. For the chemical characterization of the compounds present in CEEMT, phytochemical screening and ultra-performance liquid chromatography (UPLC) were performed. Phenotypic tests were used to analyze biofilm production, antimicrobial activity (with ethanolic extract and oxacillin) and antibiofilm, as well as synergism (checkerboard technique) and presence of efflux pump. From the analysis of the extract it was possible to identify the presence of phenolic compounds, anthocyanins, anthracene derivatives and hydrolysable tannins In the phenotypic test in microplates, all the isolates produced biofilm. The antimicrobial activity of the plant extract and oxacillin was observed in 100% of the isolates. Regarding biofilm formation, CEEMT was effective during its formation, but it was not able to revert the biofilm when it was already consolidated. In the checkerboard, it was possible to observe that the association of the extract with oxacillin was able to reduce the minimum bactericidal concentration of the antibiotic, showing that there was synergic interaction between both. Regarding the presence of efflux pump, no isolates were positive for the test. It is concluded that all the Staphylococcus aureus used in this study had the capacity to produce the biofilm, but did not present efflux pump. The ethanolic extract presented antimicrobial activity on all the isolates and also showed action against biofilm in formation, not being effective against already consolidated biofilm. Regarding the presence of efflux pump, no isolates were positive for the test. It is concluded that all the Staphylococcus aureus used in this study had the capacity to produce the biofilm, but did not present efflux pump. The association of EEBMT with oxacillin presented an important synergetic result, and the combination of the two substances proved to be more effective when compared to its use in isolation. From these results, it is possible to consider the ethanolic extract of M. tenuiflora as an important therapeutic alternative, being promising in the fight against S. aureus biofilm forming agents.