In vitro activity of allicin against Staphylococcus epidermidis and influence of subinhibitory concentrations on biofilm formation

Aims: The aim of this study is to determine the in vitro activity of allicin against Staphylococcus epidermidis and to evaluate the influence of allicin on biofilm formation. Methods and Results: In vitro activity of allicin (diallyl thiosulphinate) against 38 strains of S. epidermidis was investigated. The activity of allicin was similar against S. epidermidis methicillin susceptible and methicillin resistant strains [minimum inhibitory concentration (MIC)90 = 8 mg l−1]. In general, subinhibitory concentrations (sub‐MIC) of allicin diminished biofilm formation in the five strains analysed. Conclusion: The results confirm the antibacterial effect of allicin. Sub‐MICs of allicin also diminished the biofilm formations by S. epidermidis. Significance and Impact of the Study: The present study shows that allicin is active in vitro against S. epidermidis and that sub‐MICs of allicin may play a role in the prevention of adherence of this bacteria to medical devices.