Effect of Combinations of Antibiotics and Gallates on Biofilm Formation in Staphylococcus aureus

Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) are highly resistant to some antibiotics and it is difficult to treat infections caused by Staphylococcus aureus. This study evaluates the amount of Biofilm formation in four strains of MRSA and two strains of MSSA in presence of three antibiotics (mupirocin, tetracycline, and fusidic acid), two phytochemicals (epicatechin gallate and ethyl gallate) as single agents and in combination. Biofilm formation was quantified using spectrophotometry and visualized by Scanning Electron Microscope. Our results show that the combination of tetracycline with ethyl gallate, and tetracycline with epicatechin gallate were most effective in inhibiting the biofilm formation. It is interesting to observe that biofilm formation is inhibited significantly at synergistic concentration of combinations of antibiotics and phytochemicals. These results can be of potential therapeutic value towards development of new drugs for the prevention and treatment of infections caused by drug- resistant biofilm forming bacteria.