Synergistic effect of proanthocyanidins and cefquinoxime sulfate on methicillin-resistant Staphylococcus aureus

To address the severe problem of methicillin-resistant Staphylococcus aureus (MRSA) resistance, this study identified a single component from traditional Chinese medicine that, when used in combination with existing antibiotics, enhances the therapeutic efficacy of the antimicrobial drugs. Using the micro broth dilution method and the checkerboard dilution method, susceptibility tests were conducted on ten commonly used β-lactam antibiotics against eleven strains of MRSA. It was found that cefquinome sulfate exhibits synergistic activity with PROs. The results indicate that among the ten antibiotics tested, five-potassium penicillin, ampicillin, ceftazidime, amoxicillin and CEFS had resistance rates exceeding 70%, indicating a serious resistance situation. Synergistic antibacterial effects showed that 25μg/mL of PROs could reduce the minimum inhibitory concentration (MIC) of CEFS against MRSA strains from 8μg/mL to 1μg/mL, with a fractional inhibitory concentration index (FICI) of 0.38±0.0, thus restoring the sensitivity of MRSA. These findings suggest the need for regular and continuous monitoring of the clinical distribution and resistance of MRSA in pig farms and implementing effective measures to prevent or control MRSA infections.