# Synergistic antibacterial activity of baicalin in combination with oxacillin sodium against methicillin‐resistant Staphylococcus aureus

## TL;DR

Baicalin, a traditional Chinese medicine extract, works with oxacillin to fight drug-resistant Staphylococcus aureus by increasing antibiotic entry into bacteria.

## Contribution

The study reveals a synergistic effect between baicalin and oxacillin sodium against MRSA by enhancing bacterial membrane permeability.

## Key findings

- The combination of baicalin and oxacillin sodium showed a synergistic effect with a fractional inhibitory concentration index of 0.5.
- Baicalin increased bacterial cell wall and membrane permeability, enhancing oxacillin sodium's bactericidal action.
- The combination significantly inhibited MRSA biofilm formation by reducing polysaccharide intercellular adhesion production.

## Abstract

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.

The bacterial cell membrane and cell wall are the primary targets of baicalin. Baicalin increases the permeability of bacterial membranes, allowing oxacillin sodium to easily penetrate the cells and effectively exert its antimicrobial activity.