Controle de Staphylococcus aureus com géis à base de óleos essenciais

Abstract

The frequent use of antimicrobials, especially antibiotics to control Staphylococcus aureus, has led to the emergence of multiresistant strains. Because it is on the skin, this is one of the bacteria most present in infectious processes in wounds, making the healing process difficult. As a result, the search for alternative substances to antibiotics has intensified, with natural antimicrobials standing out in this context, especially essential oils from medicinal plants. The essential oil has several components that cause changes in the bacterial cell, promoting its death or inhibition. Therefore, essential oils are an effective therapeutic alternative for treating wounds. Therefore, this work aimed to verify the antimicrobial activity of gels made with essential oils aiming to control S. aureus. The antimicrobial activity of essential oils of thyme (Thymus vulgaris), marjoram (Origanum majorana), clove bud (Syzygium aromaticum), eucalyptus (Eucalyptus globulus), verbena (Lippia alba) and São Caetano melon extract (Momordica charantia) was evaluated on Staphylococcus aureus ATCC 25923. After determining the minimum bactericidal concentrations of essential oils and their combinations, gels were prepared with the combinations of essential oils that showed the greatest bactericidal activity. The in vitro bactericidal activity of the gels was compared with alcohol gel and determined by spreading on the surface of a stainless steel coupon containing biofilm formed by S. aureus. The minimum concentrations of bactericides determined were 2.5% for marjoram oil, 0.62% for clove oil and 1.25% for thyme and verbena oils. São Caetano melon extract did not show bactericidal activity at the concentrations tested. 27 trials were generated using the Rotational Central C Design containing different concentrations of thyme, clove, eucalyptus and verbena oils. All combinations tested inhibited the growth of S. aureus. In this way, trials 7 (thyme, 0.39%; clove, 0.31%; eucalyptus, 1.95%; and verbena, 0.39%) were chosen, 18 (thyme, 0.62%; clove, 0.31%; eucalyptus, 1.40%; and verbena, 0.46%) and 22 (thyme, 0.46%; clove, 0.31%; eucalyptus, 2.5%; and vervain, 0.46 %) to incorporate into the prepared carbopol gel, called gel 1, 2 and 3, respectively. Although gels and alcohol showed antimicrobial activity against S. aureus, a significant difference was observed between gel 3 and gels 1, 2 and alcohol. Gels 1 and 2 were the most efficient for controlling S. aureus in vitro, reducing adhered cells by between 90 and 92%. After 30 days of storing the gels, the numbers of S. aureus cells increased. These gels can be considered a possible alternative as an antiseptic and in the treatment of wounds.