In this study we aimed to investigate the relationship between the antimicrobial action of propolis and antibiotics using clinical samples of Methicillin Resistant Staphylococcus aureus (MRSA), Methicillin Sensitive Staphylococcus aureus (MSSA) and a laboratory strain of Staphylococcus aureus.The effect of propolis on the antibiotic susceptibility of MRSA/MSSA and Staph. aureus was investigated by testing antibiotic susceptibility of the strains in the presence and absence of propolis. Experimental methods included Minimum inhibitory concentration (MICs), disk diffusion assays, eTESTS and a Checkerboard method, in order to ascertain whether propolis could enhance the effects of antibiotics by establishing if the effect observed demonstrated synergy.The results showed that both MRSA and MSSA are highly sensitive to propolis with an MIC of 0.01% (w/v). The presence of propolis increased the susceptibility of these strains to antibiotics.
This novel approach of utilising this readily available and cheap natural product as a combination therapy will enhance the efficacy of current front-line antibiotics [thus enhancing minimum inhibitory concentration and reducing occurrence of resistance] and additionally offers the opportunity to re-introduce antibiotics previously side-lined due to multi drug resistance (MDR), back into the clinic as realistic therapeutic options.