Chemical Composition and Synergistic Potential of L. and Asso. Essential Oils and Antibiotic against Multi-Drug Resistant Bacteria.

The essential oils were obtained by hydrodistillation from aerial parts of L. (. L.) and () Asso. and analyzed by gas chromatography-flame ionization detector chromatograpy (GC-FID) and gaz chromatography-mass spectrometry (GC-MS). The antibacterial activities of the oils were determined by the disk diffusion method and a microdilution broth assay against six bacteria stains. The combinations of these essential oils with antibiotics were evaluated against two multi-drug-resistant bacteria strains: imipenem-resistant (IRAB S3310) and methicillin-resistant (MRSA S19). The chemical analysis of . essential oil revealed the presence of pulegone (74.8%) and neoisomenthol (10.0%). essential oil was characterized by camphor (32.0%), α-thujone (13.7%), 1,8-cineole (9.8%), β-thujone (5.0%), bornéol (3.8%), camphene (3.6%), and -cymene (2.1%). All strains tested except were susceptible to these oils. The combinations of essential oils with antibiotics exerted synergism, antagonism, or indifferent effects. The best effect was observed with essential oil in association with cefoxitin (CX) against MRSA S19. However, for IRAB S3310, the strongest synergistic effect was observed with in association with amikacin (AK). This study demonstrated that and essential oils have antibacterial activities which could be potentiated by antibiotics especially in the case of IRAB S3310.