Abstract:Nosocomial pathogens are associated with increased hospital stay lengths and mortality rates. Increasing resistance to antibiotics makes the treatment of these infections more difficult. Novel antimicrobial compounds derived from natural sources may be useful for addressing antiobiotic resistance. The objective of this study is to determine the chemical composition and antimicrobial activities of essential oils from Myrtus communis L. (Myrtaceae) leaves against pathogens causing nosocomial infections. The chemical composition of essential oil from M. communis leaves was analysed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the essential oil against bacteria and fungi was evaluated by broth micro-dilution as per the Clinical and Laboratory Standards Institute (CLSI) methods. GC-MS analysis revealed that the major constituents of the essential oil were α-pinene (39.2 %), 1,8-cineole (22.0 %), and linalool (18.4 %). The essential oil exhibited antimicrobial activity against all Gram positive and Gram negative bacteria with MICs in the range of 0.5-32 μL/mL and 8-64 μL/mL, respectively. MICs for the tested clinical and standard fungi were in the range of 0.03-16 μL/mL. The essential oil exhibited strong antibacterial and antifungal activities against all the causative agents of nosocomial infections examined, particularly against strains with antibiotic resistance. The essential oil from M. communis leaves is a potential source of novel antimicrobial agents for the treatment of nosocomial infections.