Inhibition of Biofilm Formation in Staphylococcus aureus Isolates by Quercus cerris Extracts

Implanted medical device infections caused by Staphylococcus aureus make up a major subset of device complications and therefore place a substantial burden on the United States healthcare system [1]. Staphylococcal biofilms are intrinsically resistant to conventional antibiotic therapy, and biofilm inhibitors could be used to prevent device colonization or improve therapeutic efficacy of antibiotics in treating established infections. In this study, we investigated the effect of Quercus cerris L. extracts on the process of biofilm formation. Ethnobotanical reports in southern Italy indicate that this species is used for multiple traditional medicinal applications in humans, and it is also used to treat wounds in animals [2,3]. We have found that the ethyl acetate and aqueous fractions of Q. cerris reduce biofilm formation by clinically-relevant S. aureus isolates. In addition, these extracts do not affect the growth curves of S. aureus, suggesting that the mechanism of biofilm formation is not due to antimicrobial effects.

Acknowledgements: Funding for this study was provided by NIH/NIAID R01-AI43356 to M.S.S.

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