Quantitative analysis of the cutaneous Malassezia microbiota in 770 healthy Japanese by age and gender using a real-time PCR assay.

Although the lipophilic yeasts of the genus Malassezia are part of the cutaneous microbiota in healthy individuals, they are also associated with several skin diseases, such as seborrheic dermatitis. However, the effects of age and gender on the Malassezia microbiota have not been completely elucidated. We analyzed the cutaneous Malassezia microbiota of 770 healthy Japanese using the highly accurate real-time PCR with a TaqMan probe to investigate the effects of age and gender on the Malassezia population. The numbers of Malassezia cells increased in males up to 16-18 years of age and in females to 10-12 years old, and subsequently decreased gradually in both genders until senescence. Malassezia restricta overwhelmingly predominated at ages over 16-18 years in males and 23-29 years in females. M. globosa and M. restricta together accounted for more than 70% of Malassezia spp. recovered regardless of gender. The total colonization of Malassezia and the ratio of the two major species change with age and gender in humans.