POLIDOCANOL SENSITIVITY - A POSSIBLE TOOL IN THE DIFFERENTIATION OF MALASSEZIA SPP

In recent years, the genus Malassezia was reclassified based on molecu lar data; in addition to M. furfur, M. pachydermatis and ;II. sympodia lis, four new species (M. globosa, ii. obtusa, ii. restricta, M. sloof fiae) were described. Primary keys for routine identification have rec ently been presented. Polidocanol was shown to have specific inhibitor y effects against Malassezia spp. In an agar diffusion test, type stra ins of all Malassezia species were incubated with polidocanol concentr ations between 0.01% and 10%. M. furfur strains were most resistant, w ith minimal inhibitory concentrations (MIG) ranging from 7.5% to 10%. Inhibitory concentrations of the other strains were lower by at least one factor of ten. Most sensitive were strains of M. pachydermatis (0. 05%). In a further test, polidocanol-containing olive oil was used to determine the sensitivity of Malassezia furfur and ill. sympodialis. A gain, the inhibitory concentrations for strains of M. sympodialis were one tenth of those found for M. furfur. In addition to its antifungal effects, polidocanol might therefore be a useful tool in differentiat ing Malassezia species.