LAUSR

Staphylococcus aureus is an important etiological agent for causing food poisoning leading to high mortality in the world. The sea gene is encoded in a polymorphic family of temperate bacteriophage chromosomes and became a prophage, and the transcription of this gene is associated with the life cycle of this prophage. It has been suggested that the grape polyphenols can eradicate the enterotoxin production of food-borne bacteria. This study aimed to evaluate the activity of the aqueous and alcoholic extracts of the grape seeds in inhibiting the expression of the sea gene encoding staphylococcal enterotoxin type A in S. aureus isolated from different sources. This study used five enterotoxin A producing isolates belonging to S. aureus. The results showed that minimum inhibition concentration and sub-minimum inhibition concentration of the aqueous extract were 32 and 16 µg/mL for all isolates, respectively. However, in the case of the alcoholic extract, these concentrations were 16 and 8 µg/mL for all isolates, respectively, and the results of the chemical analysis of the aqueous and alcoholic extracts confirmed that they contain active chemical compounds, such as flavonoids, alkaloids, tannins, and glycosides; moreover, they contain many functional groups according to the analysis of the infrared spectrum. Both extracts were shown to be active in inhibiting the expression of the sea gene in the isolates under study. As the results indicated, the gene expression of these isolates was inhibited by approximately 0.31-0.63 fold, and all pathogenic and environmental isolates showed a decrease in the expression of this gene. These results practically open the door to the possibility of using these extracts to inhibit the ability of S. aureus to produce these dangerous enterotoxins; thereby decreasing or preventing their pathogenicity, especially their food poisoning infections.