Inhibition of Berberine on Methicillin-Resistant Staphylococcus aureus Biofilm Formation

This study investigated the effect and possible mechanism of berberine on biofilm formation by methicillin-resistant Staphylococcus aureus . Compared with chloramphenicol, berberine showed a significantly stronger inhibitory effect on the growth of methicillin-resistant Staphylococcus aureus , and the minimum inhibition concentration and minimum bactericidal concentration for berberine were 0.05 mg/ml and 0.1 mg/ml, respectively ( p < 0.05). In addition, berberine significantly impaired biofilm formation and reduced biofilm thickness in a dose-dependent manner ( p < 0.05). Furthermore, the results of quantitative real-time polymerase chain reaction revealed that, at concentrations ranging from 20 to 120 μg/ml, berberine inhibited the expression of agrA , agrD , agrB , and agrC ( p < 0.05). The molecular regulatory mechanism of berberine inhibition may be obtained by its downregulation of the expression of agrA , agrD , agrB , and agrC , thereby inhibiting biofilm formation by methicillin-resistant Staphylococcus aureus . These findings demonstrate that berberine has a great potential as a quorum sensing inhibitor against biofilm-associated infections.