Synergistic antibacterial activity of Curcumin with antibiotics against Staphylococcus aureus

ABSTRACT

This study evaluated the synergistic antibacterial activity of Curcumin with 8 different antibiotic groups. Two reference, one clinical and ten environmental strains of Staphylococcus aureus [S. aureus] were tested. Disc diffusion assay with 25[micro]g/mL Curcumin demonstrated synergism in combination with a majority of tested antibiotics against S. aureus. However, checkerboard micro dilution assay only showed synergism, fractional inhibitory concentration index [FICI] <0.5 in three antibiotics i.e. Gentamicin, Amikacin, and Ciprofloxacin. Other antibiotics showed indifferent interactions but no antagonism was observed. In time-kill curve, appreciable reduction of bacterial cells was also observed in combination therapy [Curcumin + antibiotics] compared to monotherapy [Curcumin or antibiotic[s] alone]. The antibiotics with higher synergistic interaction with Curcumin are arranged in a decreasing order Amikacin > Gentamicin > Ciprofloxacin