[Effect of anti-seborrhea substances against Pityrosporum ovale in vitro].

Thirty strains of the lipophilic yeast Pityrosporum ovale were isolated from patients suffering from seborrhoeic dermatitis and dandruff and tested for susceptibility both to some classic antifungal agents and to several primarily non-antimycotic drugs. Minimal inhibitory concentrations (MIC) of altogether eleven agents were measured by the agar dilution technique. As expected, the tested imidazoles showed a good inhibition of growth of Pityrosporum. The most effective agents were ketoconazole (MIC 0.1 microgram/ml) and itraconazole (MIC 0.05 microgram/ml for some strains). MIC for fluconazole, clotrimazole and tioconazole were also low, indicating a good inhibition of Pityrosporum. In contrast, the range of MIC for bifonazole was moderate to high (for some strains 12.5-25 micrograms/ml). For zinc pyrithion a very good in vitro efficacy (MIC 0.78-1.56 micrograms/ml) was dedicated. The MIC for selenium disulphide was 1.56-3.13 micrograms/ml. The antipsoriatic drugs dithranol and liquor carbonis detergens also inhibited growth of all Pityrosporum ovale strains investigated but only at higher concentrations.