Synergistic antibacterial activity of baicalin in combination with oxacillin sodium against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a challenge for clinical treatment and combining antibiotics with other agents might be a promising strategy to overcome this challenge. This study explored the synergistic antibacterial activity of baicalin (traditional Chinese medicine extract) and the narrow-spectrum beta-lactam antibiotic oxacillin sodium, both of which are poorly active against MRSA in vitro. The combination of baicalin and oxacillin sodium showed a synergistic effect with a fractional inhibitory concentration index of 0.5. Mechanistically, the supplementation of baicalin increased the permeability of bacterial cell walls and cell membranes, enhancing oxacillin sodium entry and bactericidal action. The combination of baicalin and oxacillin sodium also significantly inhibited MRSA USA300 biofilm formation by further reducing polysaccharide intercellular adhesion production. Therefore, the combination of baicalin and oxacillin sodium offers a new therapeutic option for addressing clinical MRSA resistance. Further studies, including clinical trials, will be required to validate the observed in vitro results.