In Vitro Inhibition of Biofilm Formation by Staphylococcus Aureus Under the Action of Selected Plant Extracts

In our study we investigated the ability of selected plant extracts to inhibit the formation of biofilms produced by Staphylococcus aureus. In the first phase, we focused on the optimisation of conditions for the correct method of an approach. For optimisation, we standardized the culture media and the bacterial culture in order to obtain interpretable results. The TSB (Tryptone Soya Broth) medium was used for the preparation of an inoculum from the bacterial suspension. For the in vitro tests of antibiofilm activity against the species Staphylococcus aureus CCM 3953, we used propylene glycol (PG) plant extracts from sage and rosemary, prepared in three different concentrations of 0.01 %, 0.05 % and 0.1 %. The tests were implemented in microtitre plates using crystal violet dye at 0.1 % concentration for visualization of the intensity of a biofilm. The results were obtained, by spectrophotometric measurements at a wavelength of 550 nm. Both rosemary and sage plant extracts had a significant effect on the formation of a biofilm by S. aureus. The antibiofilm activity was concentration-dependent as the formation of biofilm was reduced more effectively with increasing concentration of the extracts. The best antibiofilm activity was observed with 0.1 % rosemary extract resulting in 94 % inhibition of the biofilm formation.