Background and Objective: Infections caused by resistant strains of Escherichia coli and Staphylococcus aureus, particularly those of hospital origin, represent a major challenge to healthcare systems, with their prevalence increasing in many countries worldwide. Consequently, extensive research has focused on identifying bioactive plant-derived compounds as alternatives or adjuncts to conventional antibiotics. The present study aimed to evaluate the antibacterial activity of acetone and methanol extracts of oak gall (Quercus infectoria) against clinical isolates of Escherichia coli and Staphylococcus aureus.
Methods: This experimental study was conducted on clinical isolates of Escherichia coli and Staphylococcus aureus. Following the preparation of acetone and methanol extracts of oak gall, their antibacterial activity was assessed using the agar well diffusion method by measuring the diameter of the inhibition zones. In addition, the minimum inhibitory concentration and minimum bactericidal concentration of each extract were determined. The obtained data were analyzed using analysis of variance ANOVA.
Results: The results demonstrated that increasing the concentration of the extracts significantly enhanced their inhibitory activity against the tested bacteria. Furthermore, both the methanolic and acetone extracts of oak gall exhibited greater antibacterial activity against Staphylococcus aureus than against Escherichia coli.
Conclusion: The findings of this study indicate that oak gall contains bioactive compounds with considerable antibacterial activity against the tested bacterial strains. Therefore, this plant may serve as a promising natural source for the development of antimicrobial agents and for the control of infections caused by pathogenic bacteria. Nevertheless, further studies are required to identify the active constituents and to evaluate their efficacy under in vivo conditions.