Staphylococcus aureus is one of the most resistant Gram-positive bacteria, capable of producing serious infections difficult to treat. The purpose of this paper is to show the inhibitory property of some essential oils against this species. The antibacterial action of herbal essential oils has been extensively studied but their effectiveness differs depending on the origin of the essential oil, the extraction method, and the plant parts from which the extraction was made. The essential oils used in this study are widely marketed oils from different producers. Overall, 19 essential oils were tested: oregano, garden thyme, wild thyme, lavender, peppermint, basil, rosemary, fennel, cumin, black cumin, dill, garden sage, grapefruit, bay laurel, patchouli, and tea tree. The bacteria tested for sensitivity to these essential oils was Staphylococcus aureus, obtained from the “Horia Cernescu” Research Laboratory Complex of the “King Michael I of Romania” University of Agricultural Sciences and Veterinary Medicine of Banat in Timisoara, Romania. The method used was the Kirby-Bauer diffusion method, commonly used to test the antibiotic sensitivity of various bacteria. The culture medium used to grow bacteria was supplemented with blood. For the interpretation of the results, a classification of essential oils was carried out according to the inhibition zone diameter (IZD). For oils with an IZD larger than 20 mm, Staphylococcus aureus has been characterized as highly sensitive; for a diameter between 15 and 19 mm, it has been characterized as very sensitive; in the case of diameters of 9-14 mm, it has been called sensitive; it was considered non-sensitive for diameters smaller than 8 mm. Thus, oregano, garden thyme, wild thyme, clove, and vervain oils have been classified in the extremely sensitive category. Bay laurel, patchouli, peppermint, and tea tree oils have been classified as highly sensitive, and lavender, basil, dill, rosemary, garden sage, rose geranium, and cumin oils have been classified as sensitive.

Staphylococcus aureus, essential oils, diffusion method, inhibition zone

biology

Presentation: poster