Bioassay-directed screening for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) led us to the culture broth of Enterococcus faecalis TH 10, which was isolated from a Malaysian fermentation food, Temph. The anti-MRSA component was readily extracted with ethyl acetate from the culture broth at pH 3, and the extract retained the activity when incubated overnight with various proteolytic enzymes. In addition, the extract showed poor antimicrobial activity against various lactic acid bacteria, including Enterococcus faecalis. These properties strongly suggest that the active compound is distinct from bacteriocin, an extracellularly released peptide or protein which shows potent activity against species closely related to the bacteriocin-producing strain. E. faecalis has been reported to produce bacteriocin which has strong hemolytic activity on mammalian erythrocytes, but the active component of the TH 10 strain did not mediate the lysis of rabbit and human erythrocytes.

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