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Background: Mycobacterium spp. are responsible for several diseases, particularly in immunocompromised populations. The spreading of the resistance to antimycobacterial drugs is a significant problem to the public health and requires to find out a new and innovative alternative for the treatment of drug resistant mycobacterial strains. In this study, the antimycobacterial activity of Micromeria barbata, Eucalyptus globulus and Juniperus excelsa essential oils extracted from Lebanese plants was investigated against selected Mycobacterium spp. strains. Methods: Several dilutions of the three aforementioned essential oils were studied for antimycobacterial activity against four Mycobacterium spp. strains: Mycobacterium tuberculosis subsp. tuberculosis (ATCC® 27294™), multidrug-resistant M. tuberculosis (CMUL 157), Mycobacterium kansasii Hauduroy (ATCC® 12478™) and Mycobacterium gordonae Bojalil et al. (ATCC® 14470™). Results: Even with high dilutions, all tested essential oils showed a high antimycobacterial activity against targeted strains. Our data showed that M. barbata, E. globulus and J. excelsa essential oils totally inhibit the mycobacterial growth whatever the tested strains for the dilution 1/250, 1/100 and 1/250, respectively. Conclusion: To our knowledge, this is the first study regarding the antimycobacterial activity of essential oils in Lebanon. Our data show promising results, and encourage to investigate more on these medicinal plants, especially M. barbata. Keywords: Essential oils, Antimycobacterial activity, Micromeria barbata, Eucalyptus globulus, Juniperus excelsa

International audience; This study aims to evaluate the antimicrobial activity of the essential oil of the plant Micromeria barbata (M. barbata) against the Gram negative and Gram positive bacterial strains (from wild type strains and strains that have multiple mechanisms of resistance to antibiotics), as well as against a clinical strain of Candida albicans (C. albicans). The essential oil was obtained by Clevenger steam distillation. The composition of the essential oil in question as well as the concentrations of each component was determined by GC-MS. Clinically isolated strains were used, and their sensitivity to antibiotics was determined using the well diffusion method, while the resistance mechanism was determined through molecular methods. The activity of the essential oil against all tested strains was carried out using the diffusion method, and the Minimum Inhibitory Concentration (MIC) was determined using the dilution method on agar. The results of the antimicrobial activity showed that the oil had a good activity on wild strains and on strains having different mechanisms of resistance. The oil in question has a significant activity on all tested microorganisms. The broad spectrum of the antimicrobial activity of the oil, especially that directed against multi-resistant pathogens involved in human infections, make it useful to use this oil for the formulation of new drugs used to treat microbial infections, especially infections with antibiotic-resistant strains.