ANTIBACTERIAL SUSCEPTIBILITY PATTERN OF ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS ISOLATES TO SELECTED PLANT EXTRACTS

ABSTRACT The rise in antibiotic resistance has intensified the global search for effective and natural antimicrobial alternatives. This study evaluated the antibacterial activity of aqueous extracts of Elettaria cardamomum (Masoro), Curcuma longa (Turmeric), and Syzygium aromaticum (Cloves) against clinical isolates of Escherichia coli and Staphylococcus aureus. Standard microbiological techniques, including agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays, were employed. Phytochemical screening was also carried out to identify the bioactive constituents of the plant extracts. Results revealed that all three plant extracts exhibited antibacterial activity to varying degrees. S. aromaticum showed the highest inhibitory effect with zones of inhibition measuring 17.6 mm for E. coli and 19.1 mm for S. aureus, followed by E. cardamomum, while C. longa demonstrated the least activity. The MIC and MBC values (6.25 mg/mL) and bactericidal (12.5 mg/mL) further supported the potency of clove extract, which had the lowest inhibitory and bactericidal concentrations among the tested plants. Phytochemical analysis confirmed the presence of key antimicrobial compounds such as alkaloids, flavonoids, tannins, and terpenoids. The study concludes that these plant extracts, particularly clove, possess promising antibacterial properties and may serve as potential alternatives or adjuncts to synthetic antibiotics in managing bacterial infections. Further studies on toxicity, compound isolation, and synergistic effects are recommended to support their safe and effective application in clinical settings.