Evaluation of the Antibacterial Activity of Micromeria barbata in Lebanon

Abstract 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.