The diversity and abundance of fungi and bacteria on the healthy and dandruff affected human scalp

Abstract

Dandruff is a skin condition that affects the scalp of up to half the world’s population, it is characterised by an itchy, flaky scalp and is associated with colonisation of the skin by Malassezia spp. Management of this condition is typically via antifungal therapies, however the precise role of microbes in the aggravation of the condition are incompletely characterised. Here, a combination of 454 sequencing and qPCR techniques were used to compare the scalp microbiota of dandruff and non-dandruff affected Chinese subjects. Based on 454 sequencing of the scalp microbiome, the two most abundant bacterial genera found on the scalp surface were Cutibacterium (formerly Propionibacterium) and Staphylococcus, while Malassezia was the main fungal inhabitant. Quantitative PCR (qPCR) analysis of four scalp taxa (M. restricta, M. globosa, C. acnes and Staphylococcus spp.) believed to represent the bulk of the overall population was additionally carried out. Metataxonomic and qPCR analyses were performed on healthy and lesional buffer scrub samples to facilitate assessment of whether the scalp condition is associated with differential microbial communities on the sampled skin. Dandruff was associated with greater frequencies of M. restricta and Staphylococcus spp. compared with the healthy population (p<0.05). Analysis also revealed the presence of an unclassified fungal taxon that could represent a novel Malassezia species.

Exploring the human hair follicle microbiome*

“…90 The most commonly found species are M. restricta and M. globosa, which are increased and decreased, respectively, in patients with dandruff and seborrhoeic dermatitis. 45,91 Their roles in dandruff and seborrhoeic dermatitis 15,92,93 have been attributed to the production of triglyceride lipases, which generate pro-inflammatory free fatty acids from the sebum-derived triglycerides. 94,95 Colonization by dermatophytes is also seen in disease, predominantly Trichophyton spp.…”

“…Human HFs are also densely colonized by Malassezia species (Figure 3, Table 1), with major geographical, interindividual‐ and skin region‐dependent differences in the predominant Malassezia species 90 . The most commonly found species are M. restricta and M. globosa , which are increased and decreased, respectively, in patients with dandruff and seborrhoeic dermatitis 45,91 . Their roles in dandruff and seborrhoeic dermatitis 15,92,93 have been attributed to the production of triglyceride lipases, which generate pro‐inflammatory free fatty acids from the sebum‐derived triglycerides 94,95 …”

Characteristics of healthy and androgenetic alopecia scalp microbiome: Effect of Lindera strychnifolia roots extract as a natural solution for its modulation

“…As demonstrated previously and irrespective of the scalp condition, the major component of the fungal mycobiome of both healthy and AGA scalp is the genera Malassezia (Table 2). Malassezia i s a lipophilic yeast and resident flora on the skin of humans and animals [24]. At present, 11 out of the above 17 species of Malassezia have been demonstrated to be involved in the human skin microecology.…”

Skin microbiome transplantation and manipulation: Current state of the art

“…It has been shown that some strains of the same species can be beneficial and others pathogenic to the host. Usually, in disease, not only one strain drives the pathogenicity but the change of abundance of specific strains or organisms [41] , [42] , [43] , [44] .…”