Antibacterial activity of diacetylcurcumin against Staphylococcus aureus results in decreased biofilm and cellular adhesion

Abstract

Purpose. Staphylococcus aureus infections have contributed to the global healthcare burden, particularly with regard to hospital-acquired meticillin-resistant S. aureus (MRSA) infections. Methodology. This study describes the antibacterial activity of diacetylcurcumin (DAC) against meticillin-susceptible S. aureus/MRSA biofilm formation, survival, metabolic activity and structure; its ability to prevent bacterial adhesion to human cells; and toxicity in Galleria mellonella larvae. Results. DAC showed excellent antibacterial activity, with MIC ranging between 17.3 and 34.6 mu mol l(-1), and minimum bactericidal concentration ranging between 69 and 277 mu mol l(-1). It significantly reduced bacterial biofilm survival - by 22-63% (at MIC, 10 x MIC or 100 x MIC) as compared to the 25-42% reduction by vancomycin (P<0.0001) - and severely affected biofilm cell structures, leading to damaged architecture and the formation of amorphous cell clusters. Treatment with DAC (MIC/4) decreased bacterial adhesion to HaCaT keratinocytes from 1 to 5 h (P<0.0001). Finally, DAC demonstrated low toxicity in G. mellonella at its effective anti-biofilm concentrations. Conclusion. These findings open new avenues for the study of this curcumin derivative as an excellent prototype with anti-MRSA activity.