In vitro Activity of Lithium Succinate against Malassezia furfur

OBJECTIVE: The in vitro antifungal activity of lithium succinate has been evaluated against 46 different Malassezia furfur strains, isolated from patients suffering from dandruff, seborrheic dermatitis, and pityriasis versicolor. METHODS: Minimum inhibitory concentrations of lithium succinate were measured by the agar dilution technique. RESULTS: Lithium succinate was found to be able to inhibit growth of all investigated M. furfur isolates in vitro but at much higher concentrations than those which are normally used for susceptibility testing. Minimum inhibitory concentrations between 1,250 and 10,000 micrograms/ml were determined. When compared to the 8% lithium succinate ointment, the investigated concentrations are even far below this 8% value. CONCLUSIONS: It is suggested that the effect of lithium succinate ointment in seborrheic dermatitis therapy in vivo may be at least partly due to an antifungal activity of the agent.