Water dispersible magnetite nanoparticles influence the efficacy of antibiotics against planktonic and biofilm embedded Enterococcus faecalis cells

The objective of this study was to investigate the potential of magnetic nanoparticles to potentiate, but also to accomplish a sustained and controlled drug release and subsequently improve the efficacy of antibiotics against Enterococcus faecalis, one of the most resistant opportunistic pathogens, that poses a threat to chronically infected or immunocompromised patients and is difficult to eradicate from medical devices. To our knowledge, this is the first study trying to investigate the ability of magnetite nanoparticles to improve the anti-bacterial activity of the current antibiotics against planktonic and biofilm growing E. faecalis. Our results are suggesting that the magnetite nanoparticles may be considered an effective aminoglycoside antibiotics carrier, but a complete understanding of the way in which they selectively interact with different antibiotics and with the bacterial cell is needed, in order to obtain improved strategies for elimination of E. faecalis biofilms on biomedical devices or human tissues. (C) 2013 Elsevier Ltd. All rights reserved.