Antibacterial Effects of Oregano Essential Oil (OEO) and Its Potential Applications

Essential oils (EOs) are commonly used in food industry, due that they possess antioxidative and antimicrobial properties. There are few essential oils that have been used in medicine, due to its potent antibacterial activity against intrahospital pathogens. OEO has experimentally shown potent antibacterial effect on nosocomial Gram-positive bacteria, therefore it can be very useful in hospital environments, where there are many bacterial pathogens, which are the etiological agents of nosocomial infections and most of them are resistant to several antibiotics.

Objective: The aim of this study was to determine antimicrobial effect of OEO on most frequent bacterial intrahospital pathogens: MRSA, MRSE comparatively to selected ATCC bacterial reference strains.

Methods: This experimental study investigates the antibacterial action of oregano (Origanum vulgare) essential oil (OvEO) on two human pathogens: Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) Here, we used OEO against one of the most prominent antibiotic-resistant bacterial strains: methicillin-resistant SA (MRSAmecA+ = Meticillin Resistant SA and mecA- = Meticillin Resistance SA ), methicillin-resistant SE (MRSEmecA+ = Meticillin Resistance Staphylococcus epidermidis mecA+) and reference strains: S. aureus ATCC 700699, S. epidermidis ATCC 359845 and E. coli ATCC 25922. Bactericidal effects of the OEO on these bacteria were mainly evaluated using undiluted and four serial dilutions in coconut oil (CCO) l: 1:10, 1:100, 1:200, 1:400.

Results: OEO, undiluted and 4 serial dilutions showed potent antibacterial activity against all strains tested. In conclusion, this OEO could be used as an alternative in medicine. The ability of OEO to inhibit and kill clinical Multi-Drug-Resistant (MDR): MRSA and MRSE strains, highlights it´s potential for use in the management of drug-resistant MDR infections in hospitals wards.