The influence of essential oils on Staphylococcus spp. isolated from skin microbiota

Essential oils constitute a rich source of bioactive compounds and serve as common ingredients in the cosmetic and pharmaceutical industries. Because they are often applied directly to the skin, we aimed at determining the influence of essential oils on Staphylococcus spp. isolated from healthy skin microbiota.

A microbroth dilution method was used to determine the antimicrobial activity of thyme (Thymus vulgaris L.), mellisa (Melissa officinalis L.), sage (Salvia officinalis L.), peppermint (Mentha piperita L.), tea tree (Melaleuca alternifolia) and oregano (Origanum vulgare L.) essential oils against reference staphylococci as well as 21 strains isolated from healthy skin represented by seven species: Staphylococcus saprophyticus, S. haemolyticus, S. lentus, S. warneri, S. aureus, S. epidermidis, and S. hominis.

The analysis showed that oregano and thyme essentials oils exhibited the highest antistaphylococcal activity (MIC ranging from 0.5 to 2 mg/ml), followed by tee tree and mellisa oils (MIC ranging from 2 to 8 mg/ml), and sage and peppermint oils (MIC ranging from 4 to 16 mg/ml). All tested essential oils showed bactericidal activity.

Because of the low MIC values, part of the examined essential oils showed significant antibacterial activity giving them the potential of usage as supportive agents in the treatment of skin infections. Due to high activity against commensal staphylococci, thyme as well as oregano essential oils can disrupt skin microbiota homeostasis, which underlines the necessity of careful skin application.