In VitroAntibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-ResistantStaphylococcus epidermidis

Abstract

The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils fromSalvia officinalisandSalvia sclareawere studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of threeSalviaspp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation ofin vitrointeractions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC) indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil fromSalvia officinaliswith oxacillin in methicillin-resistantStaphylococcus epidermidis.