Experimental Study on the Inhibition of Methicillin-Resistant Staphylococcus aureus Growth and Biofilm Formation by Berberine Hydrochloride Combined with Vancomycin

Abstract

Our study aimed to investigate the combined effect of berberine hydrochloride and vancomycin on Methicillin-resistant Staphylococcus aureus (MRSA) planktonic bacteria. MRSA strains were isolated from patients with periprosthetic infections. In vitro experiments were conducted to examine changes in the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the bacteria when treated with the combination. The study found that berberine hydrochloride enhanced the antibacterial effect of vancomycin against MRSA. Interestingly, sub-inhibitory concentrations of vancomycin led to increased biofilm formation of MRSA, with a more pronounced effect as the concentration decreased. Berberine hydrochloride partly increased MRSA biofilm formation when combined with sub-inhibitory concentrations of vancomycin, but it reduced the promotion of MRSA biofilm formation at MIC concentrations. Notably, the combination of berberine hydrochloride and vancomycin at MIC concentrations decreased MRSA’s adhesion ability, possibly linked to the down-regulation of biofilm formation-related genes (icaA, sarA, and cidA). Overall, these findings suggest that berberine hydrochloride, in conjunction with vancomycin, can exert an inhibitory effect against MRSA to some extent. This combination has the potential to enhance the antimicrobial activity of vancomycin and may hold promise in combating MRSA infections.