Malassezia Research Articles

Antimicrobial activity of Lactiplantibacillus plantarum APsulloc 331261 and APsulloc 331266 against pathogenic skin microbiota.

Balanced skin microbiota is crucial for maintaining healthy normal skin function; however, disruption of the balance in skin microbiota is linked with skin diseases such as atopic dermatitis, acne vulgaris, dandruff, and candidiasis. Lactoplantibacillus species with proved with health benefits are probiotics that improve the balance of microbiome in skin and gut. In the present study, we investigated the potential antimicrobial activity of Lactiplantibacillus plantarum APsulloc 331261 (APsulloc 331261) and Lactiplantibacillus plantarum APsulloc 331266 (APsulloc 331266) derived from green tea, in inhibiting five skin pathogenic strains (Staphylococcus aureus (S. aureus), Cutibacterium acnes (C. acnes), Candia albicans (C. albicans), Malassezia globosa (M. globose), and Malassezia restricta (M. restricta)) associated with skin infection. Viability of S. aureus, C. acnes, C. albicans, M. globosa, and M. restricta was inhibited by indirect co-culture with APsulloc 331261 or APsulloc 331266 at various ratios. Different concentrations of the cell-free conditioned media (CM) derived from APsulloc 331261 or APsulloc 331266 inhibited the vaibility of S. aureus, C. acnes, C. albicans, M. globosa, and M. restricta in a dose dependent manner. Moreover, susceptibility of S. aureus, C. acnes and C. albicans against APsulloc 331261 or APsulloc 331266 was confirmed following agar overlay methods. Results of the agar overlay confirmed that various concentrations of APsulloc 331261 and APsulloc 331266 exhibited low to high inhibitory activity on the growth of S. aureus (ZDI 20.3 ± 2.1-32.3 ± 2.1 mm, R value 5.7 ± 0.8-7.8 ± 1.3 mm), C. acnes (ZDI 15.0 ± 1.7-22.2 ± 1.7 mm, R value 3.2 ± 1.3-5.5 ± 1.3 mm) and C. albicans (ZDI 13.3 ± 4.0-27.0 ± 3.6 mm, R value 2.8 ± 1.9-5.5 ± 1.7 mm). Finally, standard PCR analysis identified the presence of the of plantaricin genes encoding antimicrobial peptides in APsulloc 331261 and APsulloc 331266. These results suggest that APsulloc 331261 and APsulloc 331266 has a potential effect in the improvement of the balance of skin microbiota by inhibiting skin pathogenic strains.

Broad spectrum in vitro microbicidal activity of benzoyl peroxide against microorganisms related to cutaneous diseases.

The in vitro microbicidal activity of benzoyl peroxide against Cutibacterium acnes, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Malassezia furfur, Malassezia restricta, and Malassezia globosa was investigated. These strains were incubated for 1 h in the presence of 0.25, 0.5, 1, or 2 mmol/L benzoyl peroxide in phosphate buffered saline supplemented with 0.1% glycerol and 2% Tween 80. After exposure to benzoyl peroxide, counts of viable Gram‐positive bacteria and fungi were markedly decreased, whereas counts of Gram‐negative bacteria were unchanged. Transmission electron microscopy images showed a decrease in electron density and the destruction of C. acnes and M. restricta cell walls after exposure to 2 mmol/L benzoyl peroxide. In conclusion, this study showed that benzoyl peroxide has a potent and rapid microbicidal activity against Gram‐positive bacteria and fungi that are associated with various cutaneous diseases. This suggests that the direct destruction of bacterial cell walls by benzoyl peroxide is an essential mechanism of its rapid and potent microbicidal activity against microorganisms.

Dysbiotic Lesional Microbiome With Filaggrin Missense Variants Associate With Atopic Dermatitis in India.

Background: Atopic Dermatitis (AD) has been associated with the loss of function (LoF) mutations in Filaggrin (FLG) gene and increase in relative abundance of specific microbes in the lesional skin, predominantly in Caucasians. Our study aims to determine, in Indian AD patients, (a) the prevalence of FLG LoF and missense mutations, and (b) the nature and extent of dysbiosis and altered microbial pathways with and without mutations in FLG. AD patients (n = 34) and healthy controls (n = 54) were recruited from India in this study and shotgun sequencing was carried out in a subset of samples with adequate microbiome DNA concentration. Host DNA from the same subset of samples was subjected to FLG coding region sequencing and host-microbiome association was estimated.Results: The prevalence of FLG LoFs that are associated with AD globally were significantly lesser in our cases and controls (8.6%, 0%) than those reported in Europeans (27%, 2.6%). Staphylococcus aureus was present only on AD skin [abundance in Pediatric AD: 32.86%; Adult AD: 22.17%], but not on healthy skin on which Staphylococcus hominis (Adult controls: 16.43%, Adult AD: 0.20%; p = 0.002), Cutibacterium acnes (Adult controls:10.84%, Adult AD: 0.90%; p = 0.02), and Malassezia globosa (Adult controls: 8.89%, Adult AD: 0.005%; p = 0.001) were significantly more abundant. Microbial pathways mostly associated with skin barrier permeability, ammonia production and inflammation (Arginine and Proline metabolism, Histidine Metabolism and Staphylococcus aureus infection) were significantly enriched on AD skin metagenome. These pathways are also reported to impair antimicrobial peptide activity. Among AD patients with missense single nucleotide polymorphisms harboring “potentially damaging” alleles in FLG gene, damaging allele dosage was significantly (p < 0.02) positively correlated with relative abundance of phylum_Proteobacteria up to order_Pseudomonadales and negatively correlated with phylum_Firmicutes up to species_Staphylococcus aureus.Conclusion: Our study has provided evidence that host DNA profile is significantly associated with microbiome composition in the development of AD. Species and strain level analysis showed that the microbial pathways enriched in AD cases were mostly found in MRSA strains. These evidences can be harnessed to control AD by modulating the microbiome using a personalized strategy. Our findings on the association of FLG genotypes with the microbiome dysbiosis may pave the way for a personalized strategy to provide a more effective control of AD.

Malassezia spp. induce inflammatory cytokines and activate NLRP3 inflammasomes in phagocytes.

Malassezia spp. are common eukaryotic yeasts that colonize mammalian skin. Recently, the authors and others have observed that Malassezia globosa and Malassezia restricta can be found in the intestines in the context of certain diseases, including Crohn's disease and pancreatic cancer. In order to better understand the nature of innate inflammatory responses to these yeasts, inflammatory responses induced by M. restricta and M. globosa in mouse bone marrow-derived Mϕs (BMDM) and dendritic cells (BMDC) are evaluated. While Malassezia yeasts induce proinflammatory cytokine production from both Mϕs and dendritic cells, the levels of production from BMDC were more pronounced. Both M. restricta and M. globosa activated inflammatory cytokine production from BMDC in large part through Dectin2 and CARD9 signaling, although additional receptors appear to be involved in phagocytosis and activation of reactive oxygen production in response to the yeasts. Both M. restricta and M. globosa stimulate production of pro-IL-1β as well as activation of the NLRP3 inflammasome. NLRP3 inflammasome activation by Malassezia fungi requires SYK signaling, potassium efflux and actin rearrangement. Together, the data further the understanding of the coordinated involvement of multiple innate immune receptors in recognizing Malassezia globosa and Malassezia restricta and orchestrating phagocyte inflammatory and antimicrobial responses.

Metagenomic next-generation sequencing of viruses, bacteria, and fungi in the epineurium of the facial nerve with Bell's palsy patients.

Bell's palsy (BP) represents a major cause leading to facial paralysis in the world. The etiology of BP is still unknown, and virology is the prevailing theory. The purpose of this study is to explore the pathogenic microorganisms that may be related to BP, and it is of great significance to study the pathogenesis and treatment of BP. Metagenomic next-generation sequencing (mNGS) detection was performed in the epineurium of the facial nerve of 30 BP patients who underwent facial nerve epineurium decompression. A total of 84 pathogenic microorganisms were detected in 30 clinical samples, including 4 viruses, 10 fungi, and 70 bacteria. The species with the highest detection frequency in virus was human betaherpesvirus 7 (HHV-7). The species with the highest detection frequency in Fungi was Malassezia restricta. The species with the highest detection frequency in Bacteria was Pseudomonas aeruginosa. In this study, mNGS method was firstly used to detect the pathogenic microorganisms in the epineurium of the facial nerve with BP patients. We have for the first time identified HHV-7 and aspergillus in the epineurium of the facial nerve of BP patients. These results suggest that these two pathogenic microorganisms should be considered in the pathogenesis of BP.

Identification of Malassezia species using direct PCR- sequencing on clinical samples from patients with pityriasis versicolor and seborrheic dermatitis.

Background and Purpose : Malassezia yeasts are lipophilic normal flora of the skin in humans and other warm-blooded vertebrates. This genus includes 18 species and is responsible for dermatological disorders, such as pityriasis versicolor, atopic dermatitis, seborrheic dermatitis, folliculitis, and dandruff. The aim of the present study was to identify the etiologic agents of Malassezia infections among the patients referring to the Referral Dermatology Clinic of Al-Zahra Hospital, Isfahan, Iran, during 2018-2019.Materials and Methods: For the purpose of the study, clinical specimens, including skin scrapings and dandruff, were collected and subjected to direct microscopy, culture, and polymerase chain reaction (PCR) sequencing. Direct PCR was performed on the clinical samples to amplify the D1/D2 region of 26S rDNA, using specific primers; subsequently, the amplicons were sent for sequencing.Results: This study was conducted on 120 patients with suspected pityriasis versicolor and seborrheic dermatitis, who referred to the Referral Dermatology Clinic of Al-Zahra Hospital, Isfahan, Iran, during 2018-2019. Out of this population, 50 (41.7%), 26 (52%), and 24 (48%) cases had Malassezia infection, pityriasis versicolor, and seborrheic dermatitis, respectively. Malassezia globosa was found to be the most prevalent species (n=29, 58%), followed by M. restricta (n=20, 40%), and M. arunalokei (n=1, 2%).Conclusion: The epidemiologic study was indicative of the frequency of some Malassezia species, such as M. globosa and M. restricta, in Isfahan, Iran. It can be concluded that direct PCR on clinical samples could be used as a simple, precise, effective, fast, and affordable method for research and even routine medical mycology laboratory studies.

Malassezia species may play potential roles in the pathogenesis of meibomian gland dysfunction

Meibomian gland dysfunction (MGD) is the most common cause of dry eye disease (DED). Although many factors, such as aging, androgen deficiency, bacterial colonization and drug toxicity have been demonstrated to be associated with MGD, its pathogenesis is not well understood and definite therapies are lacking. Meibomian gland is the largest lipid-secreting gland of human and is the counterpart of sebaceous gland in the eyelid. The lipophilic yeast Malassezia species (spp) habitats in sebaceous gland and is generally considered to play pathogenic roles in seborrheic dermatitis. Several mechanisms have been illuminated, including secretion of lipases, production of toxic metabolites and generation of reactive oxidative species. Anti-fungal therapy is beneficial for patients with seborrheic dermatitis. So far, no previous studies have investigated the link between Malassezia spp and MGD. But there are reports which demonstrate increased prevalence of both high delivery and obstructive MGD in patients with seborrheic dermatitis. Malassezia spp is also found to be associated with anterior blepharitis, the seborrheic inflammation of the other counterpart of sebaceous gland in the eyelid-the Zeis gland. Based on the pathogenic role of Malassezia spp and its highly lipophilic characteristic, we hypothesize that Malassezia spp may also habitat in meibomian gland and play potential pathogenic roles in MGD. Anti-fungal treatment with 2% ketoconazole cream may be potential therapy for patients with MGD. If the hypothesis can be confirmed on patients, it can provide a novel insight of the pathogenesis of MGD and hopefully trigger further investigation into the relationship between microbiota colonization and the function of meibomian gland.

Analysis of Malassezia Lipidome Disclosed Differences Among the Species and Reveals Presence of Unusual Yeast Lipids.

Malassezia yeasts are lipid dependent and part of the human and animal skin microbiome. However, they are also associated with a variety of dermatological conditions and even cause systemic infections. How these yeasts can live as commensals on the skin and switch to a pathogenic stage has long been a matter of debate. Lipids are important cellular molecules, and understanding the lipid metabolism and composition of Malassezia species is crucial to comprehending their biology and host–microbe interaction. Here, we investigated the lipid composition of Malassezia strains grown to the stationary phase in a complex Dixon medium broth. In this study, we perform a lipidomic analysis of a subset of species; in addition, we conducted a gene prediction analysis for the detection of lipid metabolic proteins. We identified 18 lipid classes and 428 lipidic compounds. The most commonly found lipids were triglycerides (TAG), sterol (CH), diglycerides (DG), fatty acids (FAs), phosphatidylcholine (PC), phosphatidylethanolamine (PE), ceramides, cholesteryl ester (CE), sphingomyelin (SM), acylcarnitine, and lysophospholipids. Particularly, we found a low content of CEs in Malassezia furfur, atypical M. furfur, and Malassezia pachydermatis and undetectable traces of these components in Malassezia globosa, Malassezia restricta, and Malassezia sympodialis. Remarkably, uncommon lipids in yeast, like diacylglyceryltrimethylhomoserine and FA esters of hydroxyl FAs, were found in a variable concentration in these Malassezia species. The latter are bioactive lipids recently reported to have antidiabetic and anti-inflammatory properties. The results obtained can be used to discriminate different Malassezia species and offer a new overview of the lipid composition of these yeasts. We could confirm the presence and the absence of certain lipid-biosynthesis genes in specific species. Further analyses are necessary to continue disclosing the complex lipidome of Malassezia species and the impact of the lipid metabolism in connection with the host interaction.

Structures of the Skin Microbiome and Mycobiome Depending on Skin Sensitivity.

Sensitive skin (SS) syndrome is a globally widespread, self-diagnosed discomfort characterized by subjective complaints. Although the skin microbiome is considered important in skin health, the relationship between the skin microbiome and skin sensitivity is still unknown. Here, we aimed to (i) investigate whether the microbiome and mycobiome of SS are distinct from those of non-sensitive skin (NS), and (ii) define the characteristics of the skin microbiome associated with skin sensitivity. A total of 42 Korean women subjects were recruited (SS, n = 23; NS, n = 19) and the microbiome/mycobiome of their right facial cheeks were analyzed. We identified the differential microbiome and mycobiome structures between SS and NS. The mycobiome of SS was more phylogenetically diverse than that of NS. Lactobacillus and Mucor racemosus were more abundant on SS than NS, whereas Malassezia restricta was less abundant. Interestingly, both skin microbiome and mycobiome varied according to the perceived skin sensitivities of the subjects. This study suggests that the skin microbiome and mycobiome are associated with skin sensitivity. Accordingly, it lays the foundation for developing microbiome-based cosmetics or remedies for individuals suffering from SS syndrome.

Factor analysis approach unveils the influencing factors of dandruff in the normal teenage population.

The aim of this study was to explore the main factors affecting the occurrence of dandruff in healthy people (nondisease-induced scalp desquamation). This study analyzed the fungal microbial diversity of the scalp in Chinese teenage volunteers and measured scalp sebum secretion, the scalp pH value, and scalp transepidermal water loss. The amount and size of dandruff were measured, and the main factors that influence dandruff in the normal population were identified using principal component analysis. The results showed that an increase in Malassezia restricta led to an increased amount of dandruff in the mild and moderate groups. Conversely, this was not found for individuals in the severe group, whose dandruff symptoms were influenced by scalp barrier function. In terms of dandruff area grouping, the pH value and the amount of sebum secretion were the main factors, with the barrier function and microbial diversity being secondary factors. Dandruff cosmetics should emphasize different treatments for different types of dandruff to achieve better antidandruff effects. The results of this study provide a new theoretical basis for the development of multiple targets for antidandruff agents aimed at the normal population.

Sensitization against skin resident fungi is associated with atopy in cholinergic urticaria patients

BackgroundCholinergic urticaria (CholU) is a common type of chronic inducible urticaria, characterized by small itchy wheals that appear upon physical exercise or passive warming. Malassezia globosa, a skin resident fungus, has been identified as an antigen that induces mast cell/basophil degranulation and wheal formation through specific IgE, in Japanese patients with atopic dermatitis and CholU. In this study we aimed in assessing the rate of IgE sensitizations against skin resident fungi in European CholU patients.MethodsWe assessed serum IgE levels to Malassezia furfur, Candida albicans and Trichophyton mentagrophytes using routine lab testing and Malassezia globosa using a newly established ELISA. We correlated the results to wheal formation and other clinical features.ResultsFour patients (of 30 tested) had elevated levels of IgE against Malassezia furfur and Candida albicans and two had elevated levels of IgE against Trichophyton mentagrophytes. Four sera (of 25 tested) had elevated levels of IgE to the Malassezia globosa antigen supMGL_1304. Sensitization to one skin fungus was highly correlated with sensitization to the other tested fungi. We saw highly significant correlations of sensitization to supMGL_1304 with wheal size in the autologous sweat skin test (rs = 0.7, P = 0.002, n = 19), the Erlangen atopy score (rs = 0.5, P = 0.03, n = 19), total IgE serum levels (rs = 0.5, P = 0.04, n = 19) and a positive screen for IgE against common airborne/inhalant allergens s (sx1; rs = 0.54, P = 0.02, n = 19).ConclusionsSensitization to skin resident fungi including Malassezia globosa is uncommon in European CholU patients, but is associated with atopy and pronounced wheal formation upon dermal contact with their own sweat.Trial registration German Clinical Trials Registry DRKS-ID: DRKS00004277

Genomic Multiplication and Drug Efflux Influence Ketoconazole Resistance in Malassezia restricta.

Malassezia restricta is an opportunistic fungal pathogen on human skin; it is associated with various skin diseases, including seborrheic dermatitis and dandruff, which are usually treated using ketoconazole. In this study, we clinically isolated ketoconazole-resistant M. restricta strains (KCTC 27529 and KCTC 27550) from patients with dandruff. To understand the mechanisms of ketoconazole resistance in the isolates, their genomes were sequenced and compared with the susceptible reference strain M. restricta KCTC 27527. Using comparative genome analysis, we identified tandem multiplications of the genomic loci containing ATM1 and ERG11 homologs in M. restricta KCTC 27529 and KCTC 27550, respectively. Additionally, we found that the copy number increase of ATM1 and ERG11 is reflected in the increased expression of these genes; moreover, we observed that overexpression of these homologs caused ketoconazole resistance in a genetically tractable fungal pathogen, Cryptococcus neoformans. In addition to tandem multiplications of the genomic region containing the ATM1 homolog, the PDR5 homolog, which encodes the drug efflux pump protein was upregulated in M. restricta KCTC 27529 compared to the reference strain. Biochemical analysis confirmed that drug efflux was highly activated in M. restricta KCTC 27529, implying that upregulation of the PDR5 homolog may also contribute to ketoconazole resistance in the strain. Overall, our results suggest that multiplication of the genomic loci encoding genes involved in ergosterol synthesis, mitochondrial iron metabolism, and oxidative stress response and overexpression of the drug efflux pumps are the mechanisms underlying ketoconazole resistance in M. restricta.

Correction to: Atopic dermatitis and autoimmunity: the occurrence of autoantibodies and their association with disease severity.

Two of the references included in this review concern antigens derived from the fungus Malassezia globosa that have also been found in human sweat.

Fungi and Oomycetes in the Irrigation Water of Forest Nurseries

The aim of the present study was to assess fungal and oomycete communities in the irrigation water of forest nurseries, focusing on plant pathogens in the hope of getting a better understanding of potential pathogenic microorganisms and spreading routes in forest nurseries. The study sites were at Anykščiai, Dubrava, Kretinga and Trakai state forest nurseries in Lithuania. For the collection of microbial samples, at each nursery five 100-L water samples were collected from the irrigation ponds and filtered. Following DNA isolation from the irrigation water filtrate samples, these were individually amplified using ITS rDNA as a marker and subjected to PacBio high-throughput sequencing. Clustering in the SCATA pipeline and the taxonomic classification of 24,006 high-quality reads showed the presence of 1286 non-singleton taxa. Among those, 895 were representing fungi and oomycetes. The detected fungi were 57.3% Ascomycota, 38.1% Basidiomycota, 3.1% Chytridiomycota, 0.8% Mucoromycota and 0.7% Oomycota. The most common fungi were Malassezia restricta E. Guého, J. Guillot &amp; Midgley (20.1% of all high-quality fungal sequences), Pezizella discreta (P. Karst.) Dennis (10.8%) and Epicoccum nigrum Link (4.9%). The most common oomycetes were Phytopythium cf. citrinum (B. Paul) Abad, de Cock, Bala, Robideau, Lodhi &amp; Lévesque (0.4%), Phytophthora gallica T. Jung &amp; J. Nechwatal (0.05%) and Peronospora sp. 4248_322 (0.05%). The results demonstrated that the irrigation water used by forest nurseries was inhabited by a species-rich but largely site-specific communities of fungi. Plant pathogens were relatively rare, but, under suitable conditions, these can develop rapidly, spread efficiently through the irrigation system and be a threat to the production of high-quality tree seedlings.

Identification of Malassezia furfur Secreted Aspartyl Protease 1 (MfSAP1) and Its Role in Extracellular Matrix Degradation.

Malassezia is the most abundant eukaryotic microbial genus on human skin. Similar to many human-residing fungi, Malassezia has high metabolic potential and secretes a plethora of hydrolytic enzymes that can potentially modify and structure the external skin environment. Here we show that the dominant secreted Malassezia protease isolated from cultured Malassezia furfur is an aspartyl protease that is secreted and active at all phases of culture growth. We observed that this protease, herein named as MfSAP1 (M. furfur secreted aspartyl protease 1) has a broader substrate cleavage profile and higher catalytic efficiency than the previously reported protease homolog in Malassezia globosa. We demonstrate that MfSAP1 is capable of degrading a wide range of human skin associated extracellular matrix (ECM) proteins and ECM isolated directly from keratinocytes and fibroblasts. Using a 3-D wound model with primary keratinocytes grown on human de-epidermized dermis, we show that MfSAP1 protease can potentially interfere with wound re-epithelization in an acute wound model. Taken together, our work demonstrates that Malassezia proteases have host-associated substrates and play important roles in cutaneous wound healing.

Establishment of a mouse model of atopic dermatitis with overgrowth Malassezia globosa

Establishment of a mouse model of atopic dermatitis with overgrowth Malassezia globosa

Bacillomycin D effectively controls growth of Malassezia globosa by disrupting the cell membrane.

Malassezia globosa is an opportunistic pathogen that causes various skin disorders, which disturbs people's life all the time, and conventional drugs are not completely satisfactory. Bacillomycin D (BD), an antifungal lipopeptide, could inhibit various fungi growth. However, the reports about its effect on M. globosa were not found yet. In this study, we showed that BD and BD-C16 (fatty acid chain had sixteen carbon atoms) completely inhibited growth of M. globosa at concentration of 64μg/ml in 15h, which was confirmed with the observation of irregular morphological change of M. globosa treated with BD. Significantly, the study on the working mechanism showed that BD induced cell death by changing cell membrane permeability and thus promoting the release of cellular contents, which may be mediated by the interaction between BD and ergosterol from membrane. Further study showed that BD reduced the overall content of cellular sterol, and interestingly, the expression of some genes involved in membrane and ergosterol synthesis were significantly upregulated, which was likely to be a feedback regulation. Besides, we found that BD had additive and synergistic effects with ketoconazole and amphotericin B, respectively, on inhibition of M. globosa, suggesting that combination use of BD with other commercial drugs could be a promising strategy to relieve skin disorders caused by M. globosa. KEY POINTS: • BD could efficiently inhibit the growth of M. globosa. • BD increases cell membrane permeability and thus promotes the release of cellular contents. • BD has additive or synergistic effect with other antifungal drugs.

Molecular epidemiology, in vitro susceptibility and exoenzyme screening of Malassezia clinical isolates.

Introduction. Malassezia folliculitis (MF) and pityriasis versicolor (PV) are common dermatoses caused by Malassezia species. Their molecular epidemiology, drug susceptibility and exoenzymes are rarely reported in China.Aim. To investigate the molecular epidemiology, drug susceptibility and enzymatic profile of Malassezia clinical isolates.Methodology. Malassezia strains were recovered from MF and PV patients and healthy subjects (HS) and identified by sequencing analysis. The minimum inhibitory concentrations (MICs) of nine antifungals (posaconazole, voriconazole, itraconazole, fluconazole, ketoconazole, miconazole, bifonazole, terbinafine and caspofungin) and tacrolimus, the interactions between three antifungals (itraconazole, ketoconazole and terbinafine) and tacrolimus, and the extracellular enzyme profile were evaluated using broth and checkerboard microdilution and the Api-Zym system, respectively.Results. Among 392 Malassezia isolates from 729 subjects (289 MF, 218 PV and 222 HS), Malassezia furfur and Malassezia globosa accounted for 67.86 and 18.88 %, respectively. M. furfur was the major species in MF and PV patients and HS. Among 60M. furfur and 50M. globosa strains, the MICs for itraconazole, posaconazole, voriconazole and ketoconazole were <1 μg ml-1. M. furfur was more susceptible to itraconazole, terbinafine and bifonazole but tolerant to miconazole compared with M. globosa (P<0.05). Synergistic effects between terbinafine and itraconazole or between tacrolimus and itraconazole, ketoconazole or terbinafine occurred in 6, 7, 6 and 9 out of 37 strains, respectively. Phosphatases, lipases and proteases were mainly secreted in 51 isolates.Conclusions. Itraconazole, posaconazole, voriconazole and ketoconazole are theagents against which there is greatest susceptibility. Synergistic effects between terbinafine and itraconazole or tacrolimas and antifungals may be irrelevant to clinical application. Overproduction of lipases could enhance the skin inhabitation of M. furfur.

Human milk mycobiota composition: relationship with gestational age, delivery mode, and birth weight.

Intestinal and human milk microbiota studies during infancy have shown variations according to geographical location, delivery mode, gestational age, and mother-related factors during pregnancy. In this study, we performed metagenomic mycobiota analyses of 44 transient and mature human milk among five different groups: mothers of normal spontaneous delivery-term (NS-T), caesarean delivery-term (CS-T), premature (PT), small for gestational age (SGA), and large for gestational age (LGA) infants. Fungi were detected in 80 out of the 88 samples. Regarding the number of observed fungal species, the NS-T group was more homogeneous (less variable) comparing the other groups (P<0.05). In the transient human milk samples, the most abundant species were Saccharomyces cerevisiae (33.3%) and Aspergillus glaucus (27.4%). While A. glaucus (33.7%) was second most abundant species in mature milk, S. cerevisiae disappeared (P<0.01) and Penicillium rubens became the most abundant species (35.5%) (P<0.05). Among the NS-T group, the most abundant species was Malassezia globosa in both transient and mature milk. In contrast, S. cerevisiae was the most abundant species in transient human milk (45.0%) in the CS-T group, but it disappeared in mature milk (P<0.01). In transient milk, M. globosa was only represented 6.0-9.0% of taxa in the PT, SGA, and LGA groups (P<0.05). In transient and mature milk in the PT, SGA and LGA groups, the most abundant species were A. glaucus and P. rubens. In mature milk samples, P. rubens is more abundant in CS-T group, PT group and LGA group, than the NS-T groups (P<0.05 for all). Although fungi constitute only a very small part of the human milk microbiome, we observed some changes that the human milk mycobiota composition varies in caesarean delivery, premature, SGA and LGA groups, comparing the normal spontaneous delivery, as well as differences between transient and mature human milk.

Loss of centromere function drives karyotype evolution in closely related Malassezia species.

Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome-chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.