Unravel the antimicrobial action of Aguaribay´s Essential oils (EO) against biofilms and planktonic cells of Staphylococcus aureus.

CUTRO, ANDREA C.; BORDÓN, ANAHÍ; CORIA, M. S.; RODRÍGUEZ, S. A.; HOLLMANN, AXEL

Congreso; L Reunión anual de la Sociedad Argentina de Biofísica.; 2022

In previous work, we showed that EO obtained from S. areira leaves has shownantibacterial activity against S. aureus. This activity was accompanied by significantchanges in the zeta potential of bacterial and model membranes. To achieve a betterunderstanding of the mechanisms of its antibacterial action, new studies in bacteria cellsand liposomes were carried out. In this context, the integrity of S. aureus was evaluated asa function of EO concentration and incubation time by fluorescence microscopy. It wasobserved an increase in permeability of cells up to 40% for the maximal EO concentrationtested, showing a time dependent behavior. On the other hand, studies of the EO effect onthe transition temperature of DMPC:DMPG (5:1) liposomes membrane by dynamicscattering light measurement and fluorescence spectroscopy of liposomal doped withlaurdan indicated the EO produced changes in lipid membrane packing, increasing thefluidity, reducing the cooperative cohesive interaction between phospholipid andincreasing access of water to the interior of the membrane. With the aim to evaluatepossible intracellular targets, the potential effect on bacterial genomic DNA and metabolicoxidative stress were also assessed. S. areira EO led to partial degradation of DNA after 24hof incubation and it was capable of inducing oxidative stress at CIM and 2 CIMconcentrations. Finally, it was observed that this EO has a biofilm inhibition effect at sub-MIC concentrations and also showed a preformed biofilm eradication effect at all the EOconcentrations assayed. The results obtained indicated that EO has several bacteriatargets, from the cell surface up to DNA, involved in the antibacterial activity observed,affecting planktonic cells and biofilms