Ethanolic extract of Clusia guttifera is bactericidal against Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic gram-positive bacterium. MRSA poses a significant risk to public health because this bacterium is resistant to beta-lactam antibiotics among others. In the United States alone, MRSA was estimated to cause 70,000 infections and 9,000 deaths yearly. Therefore, continuous drug discovery is necessary for decreasing MRSA-related infections and deaths. Our laboratory screened an extract library from the National Center for Natural Products Research to identify potential novel antimicrobials. This screen revealed that extracts from a Clusia sp. plant limited the growth of MRSA in broth culture. We therefore obtained a Clusia guttifera shrub and cultivated this plant in our greenhouse. Ethanolic extracts of this C. guttifera plant exhibited bactericidal activity against MRSA and also inhibited the growth of Enterococcus sp., another bacterium associated with drug-resistant infections. Future studies will identify the bioactive compound responsible for the antimicrobial effect that we observed here.