Antibacterial activity of epigallocatechin gallate against methicillin-resistant Staphylococcus aureus.

The antibacterial activity of epigallocatechin gallate (EGCg), a catechin, against 53 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and expressed as minimal inhibitory concentration (MIC). The MIC50 and MIC90 of the strains were found be 64 and 126 micrograms/ml, respectively by the microdilution method. A time-kill study using an isolate showed that EGCg appeared to be bacteriostatic at 1-2 x MIC and bactericidal at 6 x MIC against MRSA. In addition, the activity of EGCg was stable to various physical conditions including boiling or freezing. These findings suggest that EGCg could be a useful agent for treating MRSA infection.