RÉSUMÉ
Pseudomonas aeruginosa is a pathogenic and nosocomial bacterium responsible for serious healthcare-associated infections mainly for its resistance to antibiotics. Against this problem researches for new active substances must be continued to overcome nosocomial infections caused by P. aeruginosa. Essential oils extracted from medicinal plants are a good alternative thanks to their proved antimicrobial activities. This study aims to evaluate the antibacterial activity of five essential oils obtained from plants that grow naturally in western Algeria against antibiotic-resistant P. aeruginosa strains. The studied essential oils, obtained by hydrodistillation, were analysed for the determination of their composition using GC-MS. The antibacterial activity of the studied essential oils was evaluated by disk diffusion and broth microdilution methods against fourteen P. aeruginosa strains, of which thirteen have been isolated from clinical sources and one reference strain. The obtained results show that Cistus munbyi and Thymus lanceolatus essential oils possess a good activity against antibiotic-resistant PP. aeruginosa strains. While Origanum glandulosum, Ammoides verticillata, and Thymbra capitata were less active respectively. Thus, C. munbyi and T. lanceolatus essential oils can be considered as good alternatives treatment against nosocomial infections caused by P. aeruginosa