The effect of savory (Satureja spp.) essential oils on Pseudomonas aeruginosa virulence factors

Pseudomonas aeruginosa is one of the most common opportunistic bacteria in nosocomial infections, which has a significant resistance to antimicrobials. Due to the restrictions in the use of antibiotics, the tendency to replace them with natural products has increased. In this study, the antimicrobial effect of four species of Satureja essential oils (S. mutica, S. bachtiarica, S. rechingeri and S. khuzestanica) on virulence factors of P. aeruginosa was evaluated. The minimum inhibitory concentration of Satureja essential oils was determined by microdilution broth method against standard strains of P. aeruginosa including PAO1 and 8821M. In the following, the effect of sub-minimum inhibitory concentrations (sub-MIC) of essential oils was investigated on virulence factors of this bacterium including motility, biofilm formation and alginate, elastase, and alkaline protease production of these two strains. All four Satureja essential oils had antimicrobial effects against the standard strains of P. aeruginosa, and also sub-MIC concentrations of the essential oils significantly reduced the virulence factors production of these strains. In this study, the suitable antagonistic effects of Satureja essential oils were observed against P. aeruginosa standard strains. By further study, these essential oils can be used as an antimicrobial compound against this bacterium.