Abstract

Rapid emergence of vancomycin resistance of methicillin-resistant Staphylococcus aureus (MRSA) has made the search of a novel bioactive compound a necessity. This study aimed to determine the anti-MRSA activity of 2, 4-Di-tert-butylphenol which produced by Streptomyces sp. KB1, analyze the mode of action, including cytotoxicity against mature brine shrimp. Totally 10 clinical isolates of MRSA were used for the anti-MRSA activity testing by broth microdilution method. The mode of action and cytotoxicity of 2, 4-Ditert-butylphenol was performed by observing the tested MRSA cells with a scanning electron microscope and evaluated by the brine shrimp lethality bioassay respectively. The results indicated that 2, 4-Di-tert-butylphenol has the potent anti-MRSA activity, and the mode of action at the cell wall and also show the moderate cytotoxic activity. Its MIC, MBC and LC<inf>50</inf> values were 31.25, 31.25 and 64.85 μg/ml respectively. The obtained data also demonstrated that this compound show bactericidal anti-MRSA activity at the concentration level lower than LC<inf>50</inf> (P-value < 0.05). This study concluded that 2, 4-Di-tert-butylphenol, produced by Streptomyces sp. KB1, is the new anti-MRSA compound that can be used as a model for novel anti-MRSA drug development.