Synergistic effects of Salvia officinalis L. essential oils and antibiotics against methicillin-resistant Staphylococcus aureus

Abstract

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) due to the acquisition of resistance to current antimicrobials pose a serious challenge for therapy, and new measures to treat and prevent this infectious pathogen are of crucial importance. Plant essential oils (EOs) and their constituents are promising agents with antimicrobial properties. The aim of this study was to evaluate the antistaphylococcal effect of essential oils from Salvia officinalis using the broth-microdilution method. Essential oils of S. officinalis were isolated from the same individual, but at different life stages - young and old leaves. The effects of combinations of sub-inhibitory concentrations of oil and different antibiotics were evaluated by the checkerboard method. The results, expressed as the fractional inhibitory concentration (FIC) and index (FICI), indicate that the essential oil isolated from young leaves potentiated the inhibitory effect of antibiotics against tested MRSA strains.