Biofilm Eradication and Inhibition of Methicillin-resistant Staphylococcus Clinical Isolates by Curcumin-Chitosan Magnetic Nanoparticles

Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococci (MR-CoNS) are a clinical challenge for the treatment of healthcare-associated infections. As alternative antimicrobial options are needed, we aimed to determine the effect of curcumin-chitosan magnetic nanoparticles on the biofilm of staphylococcal clinical isolates. MRSA and CoNS clinical isolates were identified by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was performed by broth microdilution. Nanoparticles were synthesized by co-precipitation of magnetic nanoparticles (MNP) and encapsulation by ionotropic gelation of curcumin (Cur) and chitosan (Chi). Biofilm inhibition and eradication by nanoparticles with and without the addition of oxacillin was assessed on staphylococcal strains. Cur-Chi-MNP showed antimicrobial activity on planktonic cells of MRSA and MR-CoNS strains and inhibited biofilm of MRSA. The addition of OXA to Cur-Chi-MNP increased biofilm inhibition and eradication activity against all Staphylococci strains (p=0.0007); higher biofilm activity was observed in early biofilm stages. Cur-Chi-MNP showed antimicrobial and biofilm inhibition activity against S. aureus. The addition of OXA increased biofilm inhibition and eradication activity against all Staphylococci strains. A combination treatment of Cur-Chi-MNP and OXA could be potentially used to treat staphylococcal biofilm-associated infections in its early stages before the establishment of biofilm bacterial cells.