Microarray analysis of the genomic effect of eugenol on methicillin resistant Staphylococcus aureus

Background: Staphylococcus aureus is a highly adaptive human pathogen responsible for serious hospital and community acquired infectious diseases ranging from skin and soft tissue infections to complicated and life - threatening conditions such as endocarditis and toxic shock syndrome (TSS). The rapid resistance of this organism to available antibiotics over the last few decades has necessitated a constant search for more efficacious antibacterial agents. Eugenol [4- Allyl-2-methoxyphenol] belongs to the class of chemical compounds called phenylpropanoids. It is a pure to pale yellow oily liquid substance mostly extracted as an essential oil from natural products such as clove, cinnamon, nutmeg, basil and bay leaf. Eugenol has previously been shown to have antimicrobial activity against methicillin resistant Staphylococcus aureus. However, the mechanism of S. aureus has not, as yet, been elucidated – hence, the expediency of this study.Results: Global gene expression outlines in response to sub - inhibitory concentrations of eugenol were analysed using the agilent DNA microarray system to identify gene targets, most importantly essential genes involved in unique metabolic pathways. Transcriptomic analysis of fluctuating genes revealed those involved in Amino acid metabolism, fatty acid metabolism, translation and ribosomal pathways. In Amino acid metabolism for instance, the argC gene encodes for N-acetyl-gamma-glutamyl-phosphate reductase. The argC gene plays an important role in the biosynthesis of arginine from glutamate in the amino acid metabolic pathway. It is the enzyme that catalyses the third step in the latter reaction and without this process, the production of N-acetylglutamate 5-semialdehyde will not be complete from the NADP-dependent reduction of N-acetyl-5-glutamyl phosphate, which is essential for the survival of some microorganisms and plants. Conclusion: This study has enabled us to examine complete global transcriptomal responses in MRSA against eugenol. It has revealed novel information with the potential to further benefit the exploratory quest for novel targets against this pathogen, in view to the development of efficacious antimicrobial agents for the treatment of associated infections.