Monitoring spread of Malassezia infections in a neonatal intensive care unit by PCR-mediated genetic typing.

Malassezia furfur and Malassezia pachydermatis were isolated from newborn children and incubators in a neonatal intensive care unit. To assess whether persistence or frequent import of the organisms was the cause of the elevated incidence, genetic typing of the strains was performed by PCR-mediated DNA fingerprinting. By using PCR primers aimed at repeat consensus motifs, six different genotypes could be detected in a collection of six M. furfur reference strains. In the case of 10 M. pachydermatis reference strains, nine different genotypes were detected by three different PCR assays. None of these assays could document genetic differences among the clinical isolates of either M. furfur or M. pachydermatis. On the basis of these results it is concluded that within the neonatal intensive care unit the longitudinal persistence of both an M. furfur and an M. pachydermatis strain has occurred and that Malassezia species can persist on incubator surfaces for prolonged periods of time. It can be concluded that PCR fingerprinting is a Malassezia typing procedure that is to be preferred over the analysis of chromosomal polymorphisms by pulsed-field gel electrophoresis in this genus.