Background & aim: Pseudomonas aeruginosa is a gram-negative bacillus and an opportunistic pathogen that causes high mortality in immunocompromised patients. The main antimicrobial activity of Satureja khuzestanica essence is due to carvacrol phenolic components. Nanomaterials can be a good choice because of low toxicity to fight pathogenic microbes. The aim of this study was to evaluate the effect of Satureja khuzestanica essence and copper nanocomplex on the expression of alkaline protease gene in Pseudomonas aeruginosa.

Methods: In this study, minimum inhibitory concentration (MIC) of essence and nanocomplex were detected against the strains by microdilution broth method. After exposure to MIC concentration, the alteration of alkaline protease gene expression by RT-PCR was investigated. The viability percentage was determined by MTT assay method in the presence of essence and nanocomplex.

Results: The MIC of essence for standard and clinical p. aeruginosa strains was 4 and 8 μg/ml respectively, and the MIC for the standard and clinical p. aeruginosa strains was 25 and 50μg/ml, respectively. It was found that essence and nanocomplex in MIC concentration had an inhibitory effect on the expression of alkaline protease gene.

Conclusion: The results showed that the essence has a stronger antimicrobial and inhibitory effect on the expression of alkaline protease gene than the nanocomplex.