Malassezia-Associated Skin Diseases, the Use of Diagnostics and Treatment

Evaluation of an in-house pan-Malassezia quantitative PCR in human clinical samples

Althought Malassezia spp. have been involved in various pathologies, they are an integral part of the cutaneous, gut, oral, ears, nose and throat (ENT) mycobiota. Since Malassezia are difficult to grow in culture, unexhaustive molecular biology methods have been developed to detect them. The aim of the study was to evaluate an in-house pan-Malassezia quantitative polymerase chain reaction (panM-qPCR) on various clinical human samples and determine Malassezia burden in various human mycobiota. The panM-qPCR was designed to target the repeated 28S rDNA gene from all Malassezia species. We used the assay to quantify the Malassezia burden on 361 samples from 161 subjects (80 skin swabs from 10 healthy volunteers (HV), 13 samples from 2 seborrheic dermatitis patients (SD), 90 skin samples from 19 burned patients, 119 stool samples from 89 immunocompromised patients, 59 ENT samples from 41 patients). For HV, the amount of Malassezia was different according to the swabbed areas. Quantification cycle (Cq) in SD is lower than in HV. In burned patients, Cq was significantly lower compared to HV. In stool samples, 6.7% were positive for Malassezia spp. with a high Cq. For the ENT area, a higher proportion of positive specimens were detected in ear samples than in nose samples. Our findings emphasized the importance of qPCR, confirming elevated Malassezia spp. levels on individuals' faces and scalps, increased burden in SD patients and in severely burnt patients than in HV. The pan-MqPCR appears to be a promising tool for studying Malassezia in various human mycobiota.

Microbial Dysbiosis in the Skin Microbiome and Its Psychological Consequences

The homeostasis of the skin microbiome can be disrupted by both extrinsic and intrinsic factors, leading to a state of dysbiosis. This imbalance has been observed at the onset of persistent skin diseases that are closely linked to mental health conditions like anxiety and depression. This narrative review explores recent findings on the relationship between the skin microbiome and the pathophysiology of specific skin disorders, including acne vulgaris, atopic dermatitis, psoriasis, and wound infections. Additionally, it examines the psychological impact of these skin disorders, emphasizing their effect on patients' quality of life and their association with significant psychological consequences, such as anxiety, depression, stress, and suicidal ideation in the most severe cases.

Enhanced visualization of nuclear staining and cell cycle analysis for the human commensal Malassezia

Malassezia is a lipophilic commensal yeast that resides mainly on the mammalian skin and is also found to associate with the internal organs. Dysbiosis of Malassezia is related to several diseases and often escapes detection as it is difficult to culture and maintain. Malassezia cell wall differs from other budding yeasts like S. cerevisiae due to the difference in the lipid content and is difficult to transform. In this study, we present a methodology to stain Malassezia's nucleus and perform cell cycle studies. However, staining presents a challenge due to its exceptionally thick cell wall with high lipid content, hindering conventional methods. Our novel methodology addresses this challenge and enables the staining of the Malassezia nucleus with a low background. This would allow researchers to visualize the overall nuclear health specifically nuclear morphology and analyze DNA content, crucial for cell cycle progression. By employing DNA-specific dyes like DAPI or Hoechst, we can observe the nuclear structure, and using PI we can differentiate cells in distinct cell cycle phases using techniques like flow cytometry. This novel staining methodology unlocks the door for in-depth cell cycle analysis in Malassezia which has challenged us through ages being refractory to genetic manipulations, paving the way for a deeper understanding of this commensal fungus and its potential role in human health.

Malassezia furfur bloodstream infection: still a diagnostic challenge in clinical practice

The opportunistic fungus Malassezia furfur (M. furfur) can cause either cutaneous or systemic infections. We report a case of M. furfur fungemia in a 22-year-old male with T-cell Acute Lymphoblastic Leukemia (T-ALL) who developed concomitant Bacillus cereus (B. cereus) septicemia. The fungal infection was diagnosed by microscopic examination and culture-based methods, while automated blood culture systems and molecular approaches failed in identifying the fungus. Despite appropriate therapy, the patient died 18 days after the hospitalization.

Combinatory Use of hLF(1-11), a Synthetic Peptide Derived from Human Lactoferrin, and Fluconazole/Amphotericin B against Malassezia furfur Reveals a Synergistic/Additive Antifungal Effect

OBJECTIVE

The increasing resistance of Malassezia yeasts against commonly used antifungal drugs dictates the need for novel antifungal compounds. Human lactoferrin-based peptides show a broad spectrum of antimicrobial activities. Various assays were performed to find the optimal growth conditions of the yeasts and to assess cell viability, using media with low lipid content to avoid peptide binding to medium components.

METHODS

In the current study, we tested the antimicrobial susceptibility of 30 strains of M. furfur that cover the known IGS1 genotypic variation.

RESULTS

hLF(1-11) inhibited the growth of all species tested, resulting in minimum inhibitory concentrations (MIC) values ranging from 12.5 to 100 μg/mL. In the combinatory tests, the majority of fractional inhibitory concentration indexes (FIC) for the tested strains of M. furfur were up to 1.0, showing that there is a synergistic or additive effect on the efficacy of the antifungal drugs when used in combination with hLF(1-11).

CONCLUSION

Results showed that hLF(1-11) could be combined with fluconazole or amphotericin for the antimicrobial treatment of resistant strains, enhancing the potency of these antifungal drugs, resulting in an improved outcome for the patient.

A New Generation of Postbiotics for Skin and Scalp: In Situ Production of Lipid Metabolites by Malassezia

Effects of pre- and probiotics on intestinal health are well researched and microbiome-targeting solutions are commercially available. Even though a trend to appreciate the presence of certain microbes on the skin is seeing an increase in momentum, our understanding is limited as to whether the utilization of skin-resident microbes for beneficial effects holds the same potential as the targeted manipulation of the gut microflora. Here, we present a selection of molecular mechanisms of cross-communication between human skin and the skin microbial community and the impact of these interactions on the host's cutaneous health with implications for the development of skin cosmetic and therapeutic solutions. Malassezia yeasts, as the main fungal representatives of the skin microfloral community, interact with the human host skin via lipid mediators, of which several are characterized by exhibiting potent anti-inflammatory activities. This review therefore puts a spotlight on Malassezia and provides a comprehensive overview of the current state of knowledge about these fungal-derived lipid mediators and their capability to reduce aesthetical and sensory burdens, such as redness and itching, commonly associated with inflammatory skin conditions. Finally, several examples of current skin microbiome-based interventions for cosmetic solutions are discussed, and models are presented for the use of skin-resident microbes as endogenous bio-manufacturing platforms for the in situ supplementation of the skin with beneficial metabolites.

Next generation mycological diagnosis: Artificial intelligence-based classifier of the presence of Malassezia yeasts in tape strip samples

BACKGROUND

Malassezia yeasts are almost universally present on human skin worldwide. While they can cause diseases such as pityriasis versicolor, their implication in skin homeostasis and pathophysiology of other dermatoses is still unclear. Their analysis using native microscopy of skin tape strips is operator dependent and requires skill, training and significant amounts of hands-on time.

OBJECTIVES AND METHODS

To standardise and improve the speed and quality of diagnosis of Malassezia in skin tape strip samples, we sought to create an artificial intelligence-based algorithm for this image classification task. Three algorithms, each using different internal architectures, were trained and validated on a manually annotated dataset of 1113 images from 22 samples.

RESULTS

The Vision Transformer-based algorithm performed the best with a validation accuracy of 94%, sensitivity of 94.0% and specificity of 93.5%. Visualisations providing insight into the reasoning of the algorithm were presented and discussed.

CONCLUSION

Our image classifier achieved very good performance in the diagnosis of the presence of Malassezia yeasts in tape strip samples of human skin and can therefore improve the speed and quality of, and access to this diagnostic test. By expanding data sources and explainability, the algorithm could also provide teaching points for more novice operators in future.

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

Cold atmospheric plasma therapy for Malassezia folliculitis: Laboratory investigations and a randomized clinical trial

BACKGROUND

Current treatment options for Malassezia folliculitis (MF) are limited. Recent research has demonstrated the inhibitory effect of cold atmospheric plasma (CAP) on the growth of Malassezia pachydermatis in vitro, suggesting CAP as a potential therapeutic approach for managing MF.

OBJECTIVES

The objective of our study is to assess the in vitro antifungal susceptibility of Malassezia yeasts to CAP. Additionally, we aim to evaluate the efficacy and tolerability of CAP in treating patients with MF.

METHODS

We initially studied the antifungal effect of CAP on planktonic and biofilm forms of Malassezia yeasts, using well-established techniques such as zone of inhibition, transmission electron microscopy, colony count assay and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Subsequently, a randomized (1:1 ratio), active comparator-controlled, observer-blind study was conducted comparing daily CAP therapy versus itraconazole 200 mg/day for 2 weeks in 50 patients with MF. Efficacy outcomes were measured by success rate, negative microscopy rate and changes in Dermatology Life Quality Index (DLQI) and Global Aesthetic Improvement Scale (GAIS) scores. Safety was assessed by monitoring adverse events (AEs) and local tolerability.

RESULTS

In laboratory investigations, CAP time-dependently inhibited the growth of Malassezia yeasts in both planktonic and biofilm forms. Forty-nine patients completed the clinical study. At week 2, success was achieved by 40.0% of subjects in the CAP group versus 58.3% in the itraconazole group (p = 0.199). The negative direct microscopy rates of follicular samples were 56.0% in the CAP group versus 66.7% in the itraconazole group (p = 0.444). No significant differences were found in the proportion of subjects achieving DLQI scores of 0/1 (p = 0.456) or in the GAIS responder rates (p = 0.588) between the two groups. Three patients in the CAP group and one patient in the itraconazole group reported mild AEs.

CONCLUSION

CAP demonstrated significant antifungal activity against Malassezia yeasts in vitro and exhibited comparable efficacy to itraconazole in treating MF patients. Without the associated adverse effects of oral antifungal drugs, CAP can be considered a promising and safe treatment modality for MF.

Comparative analysis of the distribution and antifungal susceptibility of yeast species in cat facial hair and human nails

Zoonotic yeast species have been implicated in disease development in both humans and cats. This study analyzed the yeast mycobiota present in feline facial hair and human nails and explored potential interspecies associations. A total of 118 biological specimens were examined, including 59 feline facial hair and 59 human nail samples. DNA extraction and DNA sequencing were performed to identify the specific yeast species. The most predominant yeast species in humans and cats were selected for antifungal susceptibility testing (itraconazole, ketoconazole, miconazole, and terbinafine). The findings unveiled diverse yeast species in cats and humans. Malassezia pachydermatis (45.8%) and Malassezia furfur (30.5%) were the most common yeast species in cats and humans, respectively. However, no significant correlation was detected between the yeast species identified in cats and their owners residing in the same household (p > 0.05). Miconazole exhibited the highest minimum inhibitory concentrations (MICs) against Malassezia pachydermatis and Malassezia furfur in both cat and human isolates, whereas terbinafine showed the lowest MICs against most Malassezia pachydermatis and Malassezia furfur in both cat and human isolates. Diverse yeast species in cat facial hair and human nails suggest possible cross-contamination among humans, pets, and environments.

Case Report: Scalp pityriasis versicolor may be a neglected problem

Pityriasis versicolor, a common skin fungal infection, is typically observed on trunk and limb skin. Here, we highlight an unusual presentation: scalp involvement, often overlooked due to its asymptomatic, mildly scaly patches. We report four pediatric cases, emphasizing the potential underestimation of this scalp variant. This case series underscores the importance of considering this diagnosis in patients with unexplained scalp hypopigmentation, especially in males with short hair who may readily notice these subtle changes. The report contributes to the understanding of this variant's clinical presentation and emphasizes the need for awareness among clinicians to ensure accurate diagnosis and appropriate management.

From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences

The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.

Galleria mellonella as a superficial model for Malassezia globosa and its treatment

Introduction. Malassezia globosa is a yeast species that belongs to the mycobiota of humans and animals, associated with dermatological disorders, such as dandruff. This is a chronic scalp skin disorder characterized by flaking and itching. Treatments include commercial shampoo with different formulations that contain antifungal activities like zinc pyrithione (ZPT) or piroctone olamine (PO). The effectiveness of these formulations has been evaluated for decades for dandruff symptom relief of volunteers. To date, non-mammalian, in vivo methods exist to test formulations of these actives. Aim. To evaluate in vivo in Galleria mellonella larva, two commercial antifungal shampoos (shampoo with 1 % ZPT and 1.6 % zinc Carbonate and shampoo with 0.5 % PO) against this species. Methodology. G. mellonella larvae were inoculated with M. globosa on abraded cuticular surface. Then, integument cell viability, histological changes, and fungal burden were evaluated. Results. Larvae inoculated with M. globosa showed higher lesion melanization and tissue damage. In addition, M. globosa population showed to increase over time. Concerning the shampoo's effectiveness, both formulations significantly reduced M. globosa burden and tissue damage. Conclusion. G. mellonella larvae were allowed to evaluate M. globosa superficial infection and antifungal effectiveness. Shampoos with ZPT and PO showed a positive effect on inoculated larvae.

Evaluation of novel cosmetic shampoo formulations against Malassezia species: Preliminary results of anti-dandruff shampoo formulations

OBJECTIVES

Malassezia species are common, clinically relevant, and lipid-dependent yeasts of humans. They are also the leading causes of the dandruff problem of humans, and the azoles are used primarily in their topical and systemic treatment. Resistance to azoles is an emerging problem among Malassezia sp., which indicates the need of new drug assessments that will be effective against dandruff and limit the use of azoles and other agents in treatment. Among them, the efficacy of various combinations of piroctone olamine and climbazole against Malassezia sp. is highly important. Here, we assessed the efficacies of various piroctone olamine and climbazole formulations against Malassezia sp. in comparison with ketoconazole.

METHODS

A total of nine formulations were included in the study, where each formulation was prepared from different concentrations of piroctone olamine and climbazole and both. All formulations contained the same ingredients as water, surfactants, hair conditioning agents, and preservatives. Malassezia furfur CBS1878, Malassezia globosa CBS7874, and Malassezia sympodialis CBS9570 were tested for antifungal susceptibility of each formulation by agar diffusion method. Sizes of the inhibition zones were compared with standard medical shampoo containing 2% ketoconazole, and the data were analyzed by Dunnett's multiple-comparison test.

RESULTS

For all Malassezia sp. strains, climbazole 0.5% and piroctone olamine/climbazole (0.1%/0.1% and 0.1%/0.5%) combinations were found to have the same effect as the medical shampoo containing 2% ketoconazole. Piroctone olamine/climbazole 1.0%/0.1% formulation showed the same efficacy as 2% ketoconazole on M. furfur and M. sympodialis, while 0.1%/0.5% formulation to only M. furfur. For M. globosa, none of the formulations tested were as effective as ketoconazole.

CONCLUSION

The species distribution of Malassezia sp. varies depending on the anatomical location on the host. According to the results of this study, climbazole and piroctone olamine combinations seem to be promising options against the dandruff problem with their high antifungal/anti dandruff efficacy.

Water-filtered infrared A irradiation exerts antifungal effects on the skin fungus Malassezia

Many common skin diseases are associated with changes in the microbiota. This applies for the commensal yeast Malassezia, which is linked to a wide range of skin disorders ranging from mild dandruff to severe seborrheic and atopic dermatitis, all of which have a detrimental impact on the individuals' quality of life. While antifungal medications offer relief in many cases, the challenges of disease recurrence and the emergence of resistance to the limited range of available antifungal drugs poses a pressing need for innovative therapeutic options. Here we examined the activity of water-filtered infrared A (wIRA) irradiation against Malassezia. wIRA's antimicrobial and wound healing properties make it an attractive option for localized, non-invasive, and contact-free treatment of superficial skin infections. Irradiation of Malassezia furfur with wIRA (570-1400 nm) resulted in a reduction of the yeast's metabolic activity. When put in contact with immune cells, wIRA-irradiated M. furfur was recovered at lower counts than non-irradiated M. furfur. Likewise, wIRA irradiation of M. furfur put in contact with keratinocytes, the primary host interface of the fungus in the skin, reduced the fungal counts, while the keratinocytes were not affected by the irradiation. The combination of wIRA with the photosensitizer methyl aminolevulinate exerted an additional antifungal effect on M. furfur, irrespective of the presence or absence of keratinocytes, suggesting an enhancement of the treatment effect when used in combination. These findings suggest that wIRA holds promise as a potential therapy for skin disorders associated with Malassezia.

Fungal Head and Neck Dermatitis: Current Understanding and Management

Head and neck dermatitis (HND) is a form of atopic dermatitis (AD) that affects the seborrheic areas of the body and causes greater quality of life detriments than other types of AD. HND can be challenging to treat since first-line topical therapies may be ineffective or intolerable for long-term use on areas affected by HND while dupilumab may cause dupilumab-associated HND (DAHND). Current evidence implicates fungi, particularly Malassezia spp., in the pathogenesis of HND. Penetration of fungal antigens through the defective AD skin barrier activates the innate and adaptive immune systems to cause cutaneous inflammation via the T helper (Th)17 and/or Th2 axes. Malassezia sensitization may distinguish HND from other forms of AD. Multiple double-blind, placebo-controlled trials have shown antifungals to benefit HND, yet the persistence of symptom relief with sustained use remains unclear. Oral antifungals appear more effective than topical antifungals but may be harmful with long-term use. DAHND may also be fungal-mediated given improvement with antifungals and evidence of an overactive immune response against Malassezia in these patients. Janus kinase inhibitors are effective for HND, including DAHND, but may cause significant side effects when administered systemically. OX40/OX40L inhibitors and tralokinumab may be promising options for HND on the horizon. Demographic and environmental factors influence the host mycobiome and should be considered in future precision-medicine approaches as microbiome composition and diversity are linked to severity of HND.

Interplay of xenobiotic-degrading and antibiotic-resistant microorganisms among the microbiome found in the air, handrail, and floor of the subway station

Investigating the quality of the subway environment, especially regarding antibiotic resistance genes (ARGs) and xenobiotics, conveys ecological and health impacts. In this study, compositions and relations of microorganisms harboring ARGs and xenobiotic degradation and metabolism genes (XDGs) in the Sukhumvit subway station (MRT-SKV) in Bangkok was assessed by analyzing the taxonomic and genetic diversity of the microbiome in the air and on the surfaces of floor and handrail. The major bacteria in the MRT-SKV (including Moraxella, which was abundant in the bioaerosol and handrail samples, and Staphylococcus, which was abundant in the bioaerosol samples) were found to contain both ARGs and XDGs. The co-abundance correlation network revealed notable relationships among bacteria harboring antibiotic resistance genes (ARGs) and xenobiotic degradation genes (XDGs). Significant associations were observed between ARGs linked to glycopeptide and fluoroquinolone resistance and genes associated with benzoate, styrene, and atrazine degradation pathways, as well as between ARGs related to cephamycin, cephalosporin, and MLS resistance and XDGs associated with the cytochrome P450-dependent drug metabolism pathway. These correlations suggested that selective pressure exerted by certain xenobiotics and antibiotics can simultaneously affect both ARGs and XDGs in the environment and should favor correlations and co-survival among ARG- and XDG-containing bacteria in the environments. The correlations may occur via shared mechanisms of resistance to both xenobiotics and antibiotics. Finally, different correlation pairs were seen in different niches (air, handrail, floor) of the subway environment or different geolocations. Thus, the relationship between ARG and XDG pairs most likely depends on the unique characteristics of the niches and on the prominent types of xenobiotics and antibiotics in the subway environment. The results indicated that interactions and connections between microbial communities can impact how they function. These microorganisms can have profound effects on accumulation of xenobiotics and ARGs in the MRT-SKV.

High α-diversity of skin microbiome and mycobiome in Japanese patients with vitiligo

BACKGROUND

Vitiligo is an acquired pigmentary disorder characterized by depigmented patches on the skin that majorly impact patients' quality of life. Although its etiology involves genetic and environmental factors, the role of microorganisms as environmental factors in vitiligo pathology remains under-researched.

OBJECTIVES

Our study explored the presence of characteristic bacterial and fungal flora in vitiligo-affected skin and investigated their potential roles in vitiligo pathogenesis.

METHODS

We sequenced bacterial 16S rRNA and the fungal ITS1 region from skin swabs collected at frequently affected sites, namely the forehead and back, of patients with vitiligo. We analyzed bacterial and fungal flora in lesional and non-lesional areas of patients with vitiligo compared with corresponding sites in age- and sex-matched healthy subjects.

RESULTS

Our findings revealed elevated α-diversity in both bacterial and fungal flora within vitiligo lesions compared with healthy controls. Notably, bacterial flora exhibited a distinctive composition in patients with vitiligo, and the proportional representation of Enterococcus was inversely correlated with the degree of vitiligo progression. Gammaproteobacteria, Staphylococcus spp., and Corynebacterium spp. were more abundant in vitiligo patients, with notable Staphylococcus spp. prevalence during the stable phase on the forehead. Conversely, the proportion of Malassezia sympodialis was lower and that of Malassezia globosa was higher in the progressive phase on the back of vitiligo patients.

CONCLUSION

Our study identified some characteristic bacterial and fungal groups associated with vitiligo activity and prognosis, highlighting the potential roles of microorganisms in pathogenesis and offering insights into personalized disease-management approaches.

Decreased skin colonization with Malassezia spp. and increased skin colonization with Candida spp. in patients with severe atopic dermatitis

Background

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease in which patients are sensitized towards a plethora of allergens. The hosts fungal microbiota, the mycobiota, that is believed to be altered in patients suffering from AD acts as such an allergen. The correlation context of specific sensitization, changes in mycobiota and its impact on disease severity however remains poorly understood.

Objectives

We aim to enhance the understanding of the specific sensitization towards the mycobiota in AD patients in relation to their fungal skin colonization.

Methods

Sensitization pattern towards the Malassezia spp. and Candida albicans of 16 AD patients and 14 healthy controls (HC) were analyzed with the newly developed multiplex-assay ALEX2® and the established singleplex-assay ImmunoCAP®. We compared these findings with the fungal skin colonization analyzed by DNA sequencing of the internal transcribed spacer region 1 (ITS1).

Results

Sensitization in general and towards Malassezia spp. and C. albicans is increased in AD patients compared to HC with a quantitative difference in severe AD when compared to mild to moderate AD. Further we saw an association between sensitization towards and skin colonization with Candida spp. yet a negative correlation between sensitization towards and skin colonization with Malassezia spp.

Conclusion

We conclude that AD in general and severe AD in particular is associated with increased sensitization towards the hosts own mycobiota. There is positive correlation in Candida spp. skin colonization and negative in Malassezia spp. skin colonization when compared to AD, AD severity as well as to specific sensitization patterns.

Fungal coexistence in the skin mycobiome: a study involving Malassezia, Candida, and Rhodotorula

Evidence of fungal coexistence in humans points towards fungal adaptation to the host environment, like the skin. The human commensal Malassezia has evolved, especially residing in sebum-rich areas of the mammalian body where it can get the necessary nutrition for its survival. This fungus is primarily responsible for skin diseases like Pityriasis versicolor (PV), characterized by hypo or hyperpigmented skin discoloration and erythematous macules. In this manuscript, we report a 19-year-old healthy female who presented with a one-year history of reddish, hypopigmented, asymptomatic lesions over the chest and a raised erythematous lesion over the face. Upon clinical observation, the patient displayed multiple erythematous macules and erythematous papules over the bilateral malar area of the face, along with multiple hypopigmented scaly macules present on the chest and back. Based on the above clinical findings, a diagnosis of PV and Acne vulgaris (AV) was made. Interestingly, the patient was immunocompetent and didn't have any comorbidities. Upon isolation of skin scrapings and post-culturing, we found the existence of three fungal genera in the same region of the patient's body. We further went on to confirm the identity of the particular species and found it to represent Malassezia, Rhodotorula, and Candida. We report how Malassezia, the predominant microbial resident skin fungus, coexists with other fungal members of the skin mycobiome. This study on an applied aspect of microbiology also shows how important it is to identify the fungal organism associated with skin infections so that appropriate therapeutics can be advised to avoid cases of relapse.

Ethanolic extract from fruiting bodies of Cordyceps militaris HL8 exhibits cytotoxic activities against cancer cells, skin pathogenic yeasts, and postharvest pathogen Penicillium digitatum

Cordyceps militaris is a well-known medicinal mushroom in Asian countries. This edible fungus has been widely exploited for traditional medicine and functional food production. C. militaris is a heterothallic fungus that requires both the mating-type loci, MAT1-1 and MAT1-2, for fruiting body formation. However, recent studies also indicated two groups of C. militaris, including monokaryotic strains carrying only MAT1-1 in their genomes and heterokaryotic strains harboring both MAT1-1 and MAT1-2. These strain groups are able to produce fruiting bodies under suitable cultivating conditions. In previous work, we showed that monokaryotic strains are more stable than heterokaryotic strains in fruiting body formation through successive culturing generations. In this study, we report a high cordycepin-producing monokaryotic C. militaris strain (HL8) collected in Vietnam. This strain could form normal fruiting bodies with high biological efficiency and contain a cordycepin content of 14.43 mg/g lyophilized fruiting body biomass. The ethanol extraction of the HL8 fruiting bodies resulted in a crude extract with a cordycepin content of 69.15 mg/g. Assays of cytotoxic activity on six human cancer cell lines showed that the extract inhibited the growth of all these cell lines with the IC50 values of 6.41-11.51 µg/mL. Notably, the extract significantly reduced cell proliferation and promoted apoptosis of breast cancer cells. Furthermore, the extract also exhibited strong antifungal activity against Malassezia skin yeasts and the citrus postharvest pathogen Penicillium digitatum. Our work provides a promising monokaryotic C. militaris strain as a bioresource for medicine, cosmetics, and fruit preservation.

Modulating the skin mycobiome-bacteriome and treating seborrheic dermatitis with a probiotic-enriched oily suspension

Seborrheic dermatitis (SD) affects 2-5% of the global population, with imbalances in the skin microbiome implicated in its development. This study assessed the impact of an oily suspension containing Lactobacillus crispatus P17631 and Lacticaseibacillus paracasei I1688 (termed EUTOPLAC) on SD symptoms and the skin mycobiome-bacteriome modulation. 25 SD patients were treated with EUTOPLAC for a week. Symptom severity and skin mycobiome-bacteriome changes were measured at the start of the treatment (T0), after seven days (T8), and three weeks post-treatment (T28). Results indicated symptom improvement post-EUTOPLAC, with notable reductions in the Malassezia genus. Concurrently, bacterial shifts were observed, including a decrease in Staphylococcus and an increase in Lactobacillus and Lacticaseibacillus. Network analysis highlighted post-EUTOPLAC instability in fungal and bacterial interactions, with increased negative correlations between Malassezia and Lactobacillus and Lacticaseibacillus genera. The study suggests EUTOPLAC's potential as a targeted SD treatment, reducing symptoms and modulating the mycobiome-bacteriome composition.

A review of the gastrointestinal, olfactory, and skin abnormalities in patients with Parkinson's disease

Parkinson's disease (PD) is a complex neurodegenerative motor disorder caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. The substantia nigra is neither the first nor the only brain region affected by PD. Recent and old studies have shown that PD does not only affect the CNS; in fact, autonomic innervation in the GIT, skin, and olfactory system was found to be affected by α-synuclein pathology outside the CNS, affecting patients' quality of life. In the gastrointestinal system, dysphagia, constipation, and bacterial overgrowth in the small intestine are common in patients with PD. In addition, several skin conditions were reported in PD, including seborrheic dermatitis, rosacea, melanoma, and others. Finally, olfactory system dysfunction, such as reduced touch sensation and smell, was associated with motor abnormalities. Further high-quality studies are needed to develop reliable tests that could help in the early diagnosis of PD.

New factors affecting wound healing and recurrence after pilonidal sinus surgery in adolescents; seborrheic dermatitis and psychiatric co-occurring conditions

Postoperative wound healing problems and recurrence remain common for pilonidal sinus disease (PSD). Our study aimed to examine the effect of comorbidities in addition to the classic known factors that may affect wound complications and recurrence after PSD surgery. We retrospectively analysed 282 adolescent patients operated on in our clinic between 2014 and 2021. We gathered the postoperative wound healing patterns of the patients under four groups. With a mean age of 15.49 ± 1.45, 59.9% (n = 169) were male, 40.1% (n = 113) were female and 23.8% (n = 67) had recurrence. When examined according to the wound healing groups, 53.5% (n = 151) had an uneventful wound, 22.6% (n = 64) had prolonged wound care, 17.7% (n = 50) of the postoperative wounds did not close and had a recurrence and 6% (n = 17) had recurrence after the wound was healed. The number of sinuses, abscess presentation and the incidence of comorbid disease in group 1 were found to be statistically significantly lower than all other groups. Seborrheic dermatitis, obesity and psychiatric diagnoses showed high statistical association with group 3 and acne with group 4. In patients with seborrheic dermatitis or psychiatric diagnosis, a significant correlation was found between wound healing according to the type of surgery (p < 0.05). The wound healing patterns of these patients after total excision and primary closure surgeries were included in Group 3 with a statistically significant high rate. As two new factors, the significance of the presence of seborrheic dermatitis and psychiatric comorbidities should be evaluated in these patients whose wounds remain open postoperatively and do not respond to primary wound care and eventually relapse. Further histologic and pathologic investigations are needed for seborrheic dermatitis and PSD relation. Awareness of these diseases may change the decision of the type of surgery, and their treatment within the same time may support wound healing and ultimately reduce recurrence.

Effect of diet on the gut mycobiome and potential implications in inflammatory bowel disease

The gut microbiome is a complex, unique entity implicated in the prevention, pathogenesis, and progression of common gastrointestinal diseases. While largely dominated by bacterial populations, advanced sequencing techniques have identified co-inhabiting fungal communities, collectively referred to as the mycobiome. Early studies identified that gut inflammation is associated with altered microbial composition, known as gut dysbiosis. Altered microbial profiles are implicated in various pathological diseases, such as inflammatory bowel disease (IBD), though their role as a cause or consequence of systemic inflammation remains the subject of ongoing research. Diet plays a crucial role in the prevention and management of various diseases and is considered to be an essential regulator of systemic inflammation. This review compiles current literature on the impact of dietary modulation on the mycobiome, showing that dietary changes can alter the fungal architecture of the gut. Further research is required to understand the impact of diet on gut fungi, including the metabolic pathways and enzymes involved in fungal fermentation. Additionally, investigating whether dietary modulation of the gut mycobiome could be utilized as a therapy in IBD is essential.

Antibacterial and Antiviral Properties of Pinus densiflora Essential Oil

The Korean mountains are home to the Korean red pine (Pinus densiflora). Pine needle oil has been used as a food additive and a traditional herbal medicine; however, any health-related properties of its trunk oil remain unknown. Herein, we assessed antibacterial and antiviral properties of essential oil extracted from the trunk of P. densiflora. Th extracted oil was hydrodistilled using a Clevenger apparatus and analyzed using gas chromatography-mass spectrometry. The antimicrobial activity of the oil was tested using the microbroth dilution technique against 10 bacterial species (6 g-positive and 4 g-negative) and fungi. The extract exerted strong antimicrobial activity against Vibrio parahaemolyticus, Bacillus cereus, Listeria monocytogenes, Propionibacterium acnes, and Malassezia furfur (minimum inhibitory concentration = 10 mL/L). Additionally, it exhibited dose-dependent activity against influenza virus A and feline coronavirus. Furthermore, among 20 identified constituents accounting for 98.7% of the oil contents, the major components included 3-cyclohexene-1-methanol (10.12%), 2-(4-methylcyclohexyl)-2-propanol (9.09%), fenchone (8.14%), O-isopropyltoluene (6.35%), and isothymol methyl ether (6.14%). The P. densiflora trunk essential oil showed antibacterial and antiviral activities that depended on its chemical composition and the microbial strains tested herein. The essential oil can be used as an antimicrobial agent and disinfectant.

Management of the human hair follicle microbiome by a synthetic odorant

BACKGROUND

Human scalp hair follicles (HFs) engage in olfactory receptor (OR)-dependent chemosensation. Activation of olfactory receptor family 2 subfamily AT member 4 (OR2AT4) by the synthetic, sandalwood-like odorant Sandalore® up-regulated HF antimicrobial peptide expression of dermcidin (DCD), which had previously been thought to be produced exclusively by sweat and sebaceous glands.

OBJECTIVES

To understand if intrafollicular DCD production can be stimulated by a commonly used cosmetic odorant, thus altering human HF microbiome composition in a clinically beneficial manner.

METHODS

DCD expression was compared between fresh-frozen scalp biopsies and microdissected, full-length scalp HFs, organ-cultured in the presence/absence of the OR2AT4 agonist, Sandalore® and/or antibiotics and/or the competitive OR2AT4 antagonist, Phenirat®. Amplicon-based sequencing and microbial growth assays were performed to assess how this treatment affected the HF microbiome.

RESULTS

Synthetic odorant treatment upregulated epithelial DCD expression and exerted antimicrobial activity in human HFs ex vivo. Combined antibiotic and odorant treatment, during an ex vivo dysbiosis event, prevented HF tissue damage and favoured a more physiological microbiome composition. Sandalore®-conditioned medium, containing higher DCD content, favoured Staphylococcus epidermidis and Malassezia restricta over S. aureus and M. globosa, while exhibiting antimicrobial activity against Cutibacterium acnes. These effects were reversed by co-administration of Phenirat®.

CONCLUSIONS

We provide the first proof-of-principle that a cosmetic odorant impacts the human HF microbiome by up-regulating antimicrobial peptide production in an olfactory receptor-dependent manner. Specifically, a synthetic sandalwood-like odorant stimulates intrafollicular DCD production, likely via OR2AT4, and thereby controls microbial overgrowth. Thus, deserving further exploration as an adjuvant therapeutic principle in the management of folliculitis and dysbiosis-associated hair diseases.

Genotype-Controlled Vertical Transmission Exerts Selective Pressure on Community Assembly of Salvia miltiorrhiza

The plant's endophytic fungi play an important role in promoting host development and metabolism. Studies have shown that the factors affecting the assembly of the endophyte community mainly include host genotype, vertical transmission, and soil origin. However, we do not know the role of vertically transmitted endohytic fungi influences on the host-plant's endophytic community assembly. Salvia miltiorrhiza from three production areas were used as research objects; we constructed three production area genotypes of S. miltiorrhiza regenerated seedlings simultaneously. Based on high-throughput sequencing, we analyzed the effects of genotype, soil origin, and vertical transmission on endophytic fungal communities. The results show that the community of soil origins significantly affected the endophytic fungal community in the regenerated seedlings of S. miltiorrhiza. The influence of genotype on community composition occurs through a specific mechanism. Genotype may selectively screen certain communities into the seed, thereby exerting selection pressure on the community composition process of offspring. As the number of offspring increases gradually, the microbiota, controlled by genotype and transmitted vertically, stabilizes, ultimately resulting in a significant effect of genotype on community composition.Furthermore, we observed that the taxa influencing the active ingredients are also selected as the vertically transmitted community. Moreover, the absence of an initial vertically transmitted community in S. miltiorrhiza makes it more vulnerable to infection by pathogenic fungi. Therefore, it is crucial to investigate and comprehend the selection model of the vertically transmitted community under varying genotypes and soil conditions. This research holds significant implications for enhancing the quality and yield of medicinal plants and economic crops.

Natural alternatives from your garden for hair care: Revisiting the benefits of tropical herbs

Hair shampoos containing botanical ingredients without synthetic additives, such as parabens, petrochemicals, sulfates and silicones are more skin- and environmentally friendly. In recent years, there is a growing demand for shampoo products with botanical extracts. Shampoos with botanical extracts are well-known for their perceived health benefits. They are also generally milder, non-toxic, natural, and less likely to disrupt the hair and scalp's natural pH and oil balance. Many also believe that shampoos with botanical origins have higher standards of quality. Numerous botanical extracts had been used as natural active ingredients in cosmetic formulations to meet consumer demands. In this review, we have revisited six tropical plants commonly added as natural active ingredients in shampoo formulations: Acacia concinna, Camellia oleifera, Azadirachta indica, Emblica officinalis, Sapindus mukorossi, and Garcinia mangostana. These plants have been traditionally used for hair care, and scientific research has shown that they exhibit relevant physicochemical properties and biological activities that are beneficial for hair care and scalp maintenance.

Pityriasis Versicolor-A Narrative Review on the Diagnosis and Management

This narrative review presents a comprehensive overview of the diagnosis and management of pityriasis versicolor (PV), a common superficial fungal infection caused by the yeast Malassezia. PV is characterised by scaly hypopigmented or hyperpigmented patches, primarily affecting the upper trunk, neck, and upper arms. Regarding commensal interactions, Malassezia utilises nutrient sources without affecting the human host. In cases of pathogenicity, Malassezia can directly harm the host via virulence factors or toxins, or indirectly by triggering damaging host responses. The diagnosis typically relies on recognising characteristic clinical features. Due to the wide variability in its clinical presentation, recognising the differential diagnosis is critical. In this paper, we discuss the clinical differentials, with their dermatoscopic presentation, but also describe a range of helpful diagnostic techniques (microscopy, conventional and ultraviolet-induced fluorescence dermatoscopy, and confocal microscopy). Topical therapies are the primary treatment for PV, encompassing non-specific antifungal agents like sulphur with salicylic acid, selenium sulphide 2.5%, and zinc pyrithione. Additionally, specific topical antifungal medications with either fungicidal or fungistatic properties may also be incorporated into the topical treatment regimen, such as imidazoles, allylamines, and ciclopirox olamine. Systemic therapies might occasionally be used. Patient education and the promotion of good personal hygiene are pivotal to reduce the risk of recurrence. In recurrent cases, particularly during warmer and more humid periods, prolonged prophylaxis with topical agents should be considered.

Anti-Malassezia Drug Candidates Based on Virulence Factors of Malassezia-Associated Diseases

Malassezia is a lipophilic unicellular fungus that is able, under specific conditions, to cause severe cutaneous and systemic diseases in predisposed subjects. This review is divided into two complementary parts. The first one discusses how virulence factors contribute to Malassezia pathogenesis that triggers skin diseases. These virulence factors include Malassezia cell wall resistance, lipases, phospholipases, acid sphingomyelinases, melanin, reactive oxygen species (ROS), indoles, hyphae formation, hydrophobicity, and biofilm formation. The second section describes active compounds directed specifically against identified virulence factors. Among the strategies for controlling Malassezia spread, this review discusses the development of aryl hydrocarbon receptor (AhR) antagonists, inhibition of secreted lipase, and fighting biofilms. Overall, this review offers an updated compilation of Malassezia species, including their virulence factors, potential therapeutic targets, and strategies for controlling their spread. It also provides an update on the most active compounds used to control Malassezia species.

Unraveling bacterial and eukaryotic communities in secondary water supply systems: Dynamics, assembly, and health implications

Secondary water supply systems (SWSSs) are crucial water supply infrastructures for high-rise buildings in metropolitan cities. In recent years, they have garnered public attention due to increased microbial risks. However, our understanding of SWSS microbial ecology, particularly concerning the composition of eukaryotes and the underlying mechanisms driving microbial dynamics and assembly in SWSSs, remains elusive. Herein, we conducted a comprehensive investigation on both eukaryotes and bacteria along the water transportation pathway and across various microbial habitats (water, biofilm, and sediment) in SWSSs. Sequencing results revealed that eukaryotes within SWSSs predominantly consist of protists (average abundance: 31.23%) and metazoans (20.91%), while amoebae accounted for 4.71% of the total. During water transportation from the distribution mains to taps, both bacterial and eukaryotic communities exhibited significant community shifts, and higher degrees of variation were observed for eukaryotic community among different locations within SWSSs. The normalized stochasticity ratio (NST) analysis demonstrated that bacterial community assembly was governed by stochastic processes, while eukaryotic community assembly was primarily shaped by deterministic processes. Within SWSS tanks, bacterial communities significantly varied across water, biofilm, and sediment, whereas eukaryotic communities showed minor differences among these habitats. The co-occurrence networks analysis revealed that tank biofilm and sediment harbored more eukaryote-bacterium linkages than water, suggesting biofilm and sediment might be hotspots for inter-kingdom interactions. We also applied FEAST analysis to track the source of tap water microbiota, results of which showed that household-tap bacteria mainly originated from tank water. In contrast, tank biofilm was identified as the primary microbial source to eukaryotes in household tap water. Additionally, engineering factors such as tank materials significantly affected amoeba community, and the SWSS configuration was found to influence Legionella and Mycobacterium abundances in SWSSs. Overall, results of our study shed light on the microbial ecology in SWSS and provide insights into SWSS management and health risk control.

Skincare potential of a sustainable postbiotic extract produced through sugarcane straw fermentation by Saccharomyces cerevisiae

Postbiotics are defined as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." They can be produced by fermentation, using culture media with glucose (carbon source), and lactic acid bacteria of the genus Lactobacillus, and/or yeast, mainly Saccharomyces cerevisiae as fermentative microorganisms. Postbiotics comprise different metabolites, and have important biological properties (antioxidant, anti-inflammatory, etc.), thus their cosmetic application should be considered. During this work, the postbiotics production was carried out by fermentation with sugarcane straw, as a source of carbon and phenolic compounds, and as a sustainable process to obtain bioactive extracts. For the production of postbiotics, a saccharification process was carried out with cellulase at 55°C for 24 h. Fermentation was performed sequentially after saccharification at 30°C, for 72 h, using S. cerevisiae. The cells-free extract was characterized regarding its composition, antioxidant activity, and skincare potential. Its use was safe at concentrations below ~20 mg mL-1 (extract's dry weight in deionized water) for keratinocytes and ~ 7.5 mg mL-1 for fibroblasts. It showed antioxidant activity, with ABTS IC50 of 1.88 mg mL-1 , and inhibited elastase and tyrosinase activities by 83.4% and 42.4%, respectively, at the maximum concentration tested (20 mg mL-1 ). In addition, it promoted the production of cytokeratin 14, and demonstrated anti-inflammatory activity at a concentration of 10 mg mL-1 . In the skin microbiota of human volunteers, the extract inhibited Cutibacterium acnes and the Malassezia genus. Shortly, postbiotics were successfully produced using sugarcane straw, and showed bioactive properties that potentiate their use in cosmetic/skincare products.

Fungal dysbiosis and decreased tear mucin at the conjunctiva in patients with conjunctival mucosa-associated lymphoid tissue lymphoma

OBJECTIVE

This study aimed to examine the differences in the fungal microbiome between patients with conjunctival mucosa-associated lymphoid tissue (MALT) and healthy controls using metagenomic analysis.

METHODS AND ANALYSIS

This case-control study was conducted at Osaka University Hospital in Osaka, Japan, from April 2015 to March 2022. Twenty-five consecutive patients with conjunctival MALT lymphoma and 25 healthy volunteers were included. Metagenomic analysis using Internal Transcribed Spacer (ITS)1 deep sequencing and hierarchical clustering was performed to investigate differences in the fungal microbiome. To assess tear environmental change, we measured tear mucin concentrations using ELISA.

RESULTS

Detailed analyses showed fungal dysbiosis and changes in β-diversity within the conjunctiva of patients with conjunctival MALT lymphoma. Hierarchical clustering revealed that the participants could be divided into three clusters according to the Malassezia abundance: cluster I (Malassezia abundance above 70%), cluster II (Malassezia abundance 25%-70%) and cluster II (Malassezia abundance below 25%). Most patients were included in cluster I, whereas most of healthy controls were included in cluster III. The differences were significant. Tear mucin concentrations were significantly lower in patients with MALT compared with healthy controls.

CONCLUSION

The metagenomic analysis using ITS1 deep sequencing was useful for identifying the differences in commensal fungi between patients with MALT lymphoma and healthy individuals. The increased prevalence of the Malassezia genus and the decreased levels of tear mucin can lead to an allergic response of the conjunctiva, resulting in the pathogenesis associated with conjunctival MALT lymphoma. Therefore, it may be beneficial to initiate treatment when a high abundance Malassezia is detected.

In vitro sensitivity of Malassezia furfur isolates from HIV-positive and negative patients to antifungal agents

INTRODUCTION

Malassezia is a lipophilic and lipid-dependent yeast genus belonging to the skin microbiota of humans and other animals. However, due to dysbiosis processes or other factors in the host, this yeast can cause different pathologies, ranging from skin diseases, such as seborrheic dermatitis, to fungemia. Isolation of Malassezia furfur has been reported in HIV-positive patients with or without skin lesions. Due to its opportunistic nature and its variable resistance to antifungal compounds, it is relevant to know the Malassezia sensitivity profiles.

OBJECTIVE

To determine the sensitivity to different antifungal agents, of clinical isolates of M. furfur obtained from HIV-positive or negative patients, with or without seborrheic dermatitis.

MATERIALS AND METHODS

Assessment of isolates sensitivity to itraconazole, voriconazole, fluconazole, and amphotericin B was performed by two techniques: (1) Broth microdilution using Clinical and Laboratory Standards Institute (CLSI) protocol M27-A3 with modifications; and (2) agar tests using Etest®.

RESULTS

Isolates obtained from HIV patients showed an increase in the minimum inhibitory concentration of fluconazole, voriconazole, and amphotericin B, compared with those of non-HIV patients. Itraconazole was the antifungal with the lowest minimum inhibitory concentration (MIC) in most isolates.

CONCLUSION

We observed differences in the sensitivity profiles of M. furfur isolates according to the context of the patient. High MIC of antifungals like fluconazole, commonly used for treating pathologies caused by Malassezia, were identified.

Antimicrobial Susceptibility Testing for Three Malassezia Species

The Malassezia genus comprises lipid-dependent yeasts that have long been associated with common skin diseases, and have recently been linked with Crohn's disease and certain cancers. Understanding Malassezia susceptibility to diverse antimicrobial agents is crucial for identifying effective antifungal therapies. Here, we tested the efficacy of isavuconazole, itraconazole, terbinafine, and artemisinin against three Malassezia species: M. restricta, M. slooffiae, and M. sympodialis. Using broth microdilution, we found antifungal properties for the two previously unstudied antimicrobials: isavuconazole and artemisinin. Overall, all Malassezia species were particularly susceptible to itraconazole, with a MIC range from 0.007 to 0.110 μg/mL. IMPORTANCE The Malassezia genus is known to be involved in a variety of skin conditions and has recently been associated with diseases such as Crohn's disease, pancreatic ductal carcinoma, and breast cancer. This work was completed to assess susceptibility to a variety of antimicrobial drugs on three Malassezia species, in particular Malassezia restricta, which is an abundant Malassezia species both on human skin and internal organs and has been implicated in Crohn's disease. We tested two previously unstudied drugs and developed a new testing method to overcome current limitations for measuring growth inhibition of slow-growing Malassezia strains.

Deciphering the roles of aryl hydrocarbon receptor (AHR) in regulating carcinogenesis

Aryl hydrocarbon receptor (AHR) is a ligand-dependent receptor that belongs to the superfamily of basic helix-loop-helix (bHLH) transcription factors. The activation of the canonical AHR signaling pathway is known to induce the expression of cytochrome P450 enzymes, facilitating the detoxification metabolism in the human body. Additionally, AHR could interact with various signaling pathways such as epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), hypoxia-inducible factor-1α (HIF-1α), nuclear factor ekappa B (NF-κβ), estrogen receptor (ER), and androgen receptor (AR) signaling pathways. Over the past 30 years, several studies have reported that various chemical, physical, or biological agents, such as tobacco, hydrocarbon compounds, industrial and agricultural chemical wastes, drugs, UV, viruses, and other toxins, could affect AHR expression or activity, promoting cancer development. Thus, it is valuable to overview how these factors regulate AHR-mediated carcinogenesis. Current findings have reported that many compounds could act as AHR ligands to drive the expressions of AHR-target genes, such as CYP1A1, CYP1B1, MMPs, and AXL, and other targets that exert a pro-proliferation or anti-apoptotic effect, like XIAP. Furthermore, some other physical and chemical agents, such as UV and 3-methylcholanthrene, could promote AHR signaling activities, increasing the signaling activities of a few oncogenic pathways, such as the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathways. Understanding how various factors regulate AHR-mediated carcinogenesis processes helps clinicians and scientists plan personalized therapeutic strategies to improve anti-cancer treatment efficacy. As many studies that have reported the roles of AHR in regulating carcinogenesis are preclinical or observational clinical studies that did not explore the detailed mechanisms of how different chemical, physical, or biological agents promote AHR-mediated carcinogenesis processes, future studies should focus on conducting large-scale and functional studies to unravel the underlying mechanism of how AHR interacts with different factors in regulating carcinogenesis processes.

The Fungal Microbiome of the Upper Airway Is Associated With Future Loss of Asthma Control and Exacerbation Among Children With Asthma

BACKGROUND

Accumulating evidence suggests that the upper airway bacterial microbiota is implicated in asthma inception, severity, and exacerbation. Unlike bacterial microbiota, the role of the upper airway fungal microbiome (mycobiome) in asthma control is poorly understood.

RESEARCH QUESTION

What are the upper airway fungal colonization patterns among children with asthma and their relationship with subsequent loss of asthma control and exacerbation of asthma?

STUDY DESIGN AND METHODS

The study was coupled with the Step Up Yellow Zone Inhaled Corticosteroids to Prevent Exacerbations (ClinicalTrials.gov Identifier: NCT02066129) clinical trial. The upper airway mycobiome was investigated using Internal transcribed spacer 1 (ITS1) sequencing of nasal blow samples collected from children with asthma when asthma was well controlled (baseline, n = 194) and during early signs of loss of asthma control (yellow zone [YZ], n = 107).

RESULTS

At baseline, 499 fungal genera were detected in the upper airway samples, with two commensal fungal species, Malassezia globosa and Malassezia restricta, being most dominant. The relative abundance of Malassezia species varies by age, BMI, and race. Higher relative abundance of M globosa at baseline was associated with lower risk of future YZ episodes (P = .038) and longer time to development of first YZ episode (P = .022). Higher relative abundance of M globosa at YZ episode was associated with lower risk of progression from YZ episode to severe asthma exacerbation (P = .04). The upper airway mycobiome underwent significant changes from baseline to YZ episode, and increased fungal diversity was correlated highly with increased bacterial diversity (ρ = 0.41).

INTERPRETATION

The upper airway commensal mycobiome is associated with future asthma control. This work highlights the importance of the mycobiota in asthma control and may contribute to the development of fungi-based markers to predict asthma exacerbation.

Bioprospecting the Skin Microbiome: Advances in Therapeutics and Personal Care Products

Bioprospecting is the discovery and exploration of biological diversity found within organisms, genetic elements or produced compounds with prospective commercial or therapeutic applications. The human skin is an ecological niche which harbours a rich and compositional diversity microbiome stemming from the multifactorial interactions between the host and microbiota facilitated by exploitable effector compounds. Advances in the understanding of microbial colonisation mechanisms alongside species and strain interactions have revealed a novel chemical and biological understanding which displays applicative potential. Studies elucidating the organismal interfaces and concomitant understanding of the central processes of skin biology have begun to unravel a potential wealth of molecules which can exploited for their proposed functions. A variety of skin-microbiome-derived compounds display prospective therapeutic applications, ranging from antioncogenic agents relevant in skin cancer therapy to treatment strategies for antimicrobial-resistant bacterial and fungal infections. Considerable opportunities have emerged for the translation to personal care products, such as topical agents to mitigate various skin conditions such as acne and eczema. Adjacent compound developments have focused on cosmetic applications such as reducing skin ageing and its associated changes to skin properties and the microbiome. The skin microbiome contains a wealth of prospective compounds with therapeutic and commercial applications; however, considerable work is required for the translation of in vitro findings to relevant in vivo models to ensure translatability.

Part 1: Understanding the role of Malassezia spp. in skin disorders: Malassezia yeasts as commensal or pathogenic organisms of human and animal skin

INTRODUCTION

Malassezia spp. are a group of lipid-dependent basidiomycetes yeasts acting as commensal organisms of the human and animal skin. However, under some not well-defined circumstances, these yeasts may switch to opportunistic pathogens triggering a number of skin disorders with different clinical presentations. The genus comprises of 18 lipid-dependent species with a variable distribution in the hosts and pathologies thus suggesting a host- and microbe-specific interactions.

AREA COVERED

This review highlighted and discussed the most recent literature regarding the genus Malassezia as a commensal or pathogenic organisms highlighting Malassezia-associated skin disorders in humans and animals and their antifungal susceptibility profile. A literature search of Malassezia associated skin disorders was performed via PubMed and Google scholar (up to May 2023), using the different keywords mainly associated with Malassezia skin disorders and Malassezia antifungal resistance.

EXPERT OPINION

Malassezia yeasts are part of the skin mycobiota and their life cycle is strictly associated with the environment in which they live. The biochemical, physiological, or immunological condition of the host skin selects Malassezia spp. or genotypes able to survive in a specific environment by changing their metabolisms, thus producing virulence factors or metabolites which can cause skin disorders with different clinical presentations.

Part 2: Understanding the role of Malassezia spp. in skin disorders: pathogenesis of Malassezia associated skin infections

INTRODUCTION

Malassezia is a major component of the skin microbiome, a lipophilic symbiotic organism of the mammalian skin, which can switch to opportunistic pathogens triggering multiple dermatological disorders in humans and animals. This phenomenon is favored by endogenous and exogenous host predisposing factors, which may switch Malassezia from a commensal to a pathogenic phenotype.

AREA COVERED

This review summarizes and discusses the most recent literature on the pathogenesis of Malassezia yeasts, which ultimately results in skin disorders with different clinical presentation. A literature search of Malassezia pathogenesis was performed via PubMed and Google scholar (up to May 2023), using the following keywords: Pathogenesis and Malassezia;host risk factors and Malassezia, Malassezia and skin disorders; Malassezia and virulence factors: Malassezia and metabolite production; Immunology and Malassezia.

EXPERT OPINION

Malassezia yeasts can maintain skin homeostasis being part of the cutaneous mycobiota; however, when the environmental or host conditions change, these yeasts are endowed with a remarkable plasticity and adaptation by modifying their metabolism and thus contributing to the appearance or aggravation of human and animal skin disorders.

Dermatopathology and the Diagnosis of Fungal Infections

Diagnosis of superficial/cutaneous fungal infections from skin, hair and nail samples is generally achieved using microscopy and culture in a microbiology laboratory, however, any presentation that is unusual or subcutaneous is sampled by taking a biopsy. Using histological techniques a tissue biopsy enables a pathologist to perform a full examination of the skin structure, detect any inflammatory processes or the presence of an infectious agent or foreign body. Histopathological examination can give a presumptive diagnosis while a culture result is pending, and may provide valuable diagnostic information if culture fails. This review demonstrates how histopathology contributes to the diagnosis of fungal infections from the superficial to the life threatening.

Colored stains: Microbial survey of cellulose-based and lignin rich papers

During the centuries diverse types of paper were produced and were characterized by a different ratio of natural macromolecules, mainly lignin and cellulose. Handmade paper has a higher content of cellulose respect to the early machine-made paper, where the lignin is the other important component. Microorganisms are able to colonize and deteriorate both types of papers. They can release on their surfaces pigments and colorants which produced anesthetic stains. The microbiota colonising 17 stains on handmade and machine-made paper surfaces together with that in library and archive environments was analyzed. Combination of microbiological and high-throughput sequencing (HTS) approaches were applied. The culture-dependent methodology comprised: isolation, DNA identification, hydrolytic and paper staining assays. The HTS was performed by MinION platform and for the mycobiome a more suitable bioinformatics analysis pipeline, MetONTIIME based on QIIME2 framework, was applied. The paper model staining assay permitted the direct recognition of colorizing isolates which in combination with sequencing data evidenced a complex microbial community able to stain the two types of paper. Staining abilities were confirmed by frequently isolated and detected fungi and also by new ones such as Roussoella euonymi and Achaetomium. We have also evidenced the staining ability of several bacteria.

Interactions between Malassezia and New Therapeutic Agents in Atopic Dermatitis Affecting Skin Barrier and Inflammation in Recombinant Human Epidermis Model

Several studies have reported the pathogenic role of Malassezia in atopic dermatitis (AD); the significance of Malassezia’s influence on AD needs to be further investigated. Dupilumab, a monoclonal antibody to anti-Interleukin (IL) 4Rα, and ruxolitinib, a Janus kinase (JAK)1/2 inhibitor, are the first approved biologics and inhibitors widely used for AD treatment. In this study, we aimed to investigate how Malassezia Restricta (M. restricta) affects the skin barrier and inflammation in AD and interacts with the AD therapeutic agents ruxolitinib and anti-IL4Rα. To induce an in vitro AD model, a reconstructed human epidermis (RHE) was treated with IL-4 and IL-13. M. restricta was inoculated on the surface of RHE, and anti-IL4Rα or ruxolitinib was supplemented to model treated AD lesions. Histological and molecular analyses were performed. Skin barrier and ceramide-related molecules were downregulated by M. restricta and reverted by anti-IL4Rα and ruxolitinib. Antimicrobial peptides, VEGF, Th2-related, and JAK/STAT pathway molecules were upregulated by M. restricta and suppressed by anti-IL4Rα and ruxolitinib. These findings show that M. restricta aggravated skin barrier function and Th2 inflammation and decreased the efficacy of anti-IL4Rα and ruxolitinib.

Position statement: Recommendations on the diagnosis and treatment of Malassezia folliculitis

Malassezia is a lipophilic yeast that is a part of the human mycobiome. Malassezia folliculitis appears when the benign colonization of the hair follicles, by the Malassezia yeasts, becomes symptomatic with pruritic papules and pustules. Although Malassezia folliculitis is common in hospital departments, diagnosing and treating it varies among dermatologists and countries. The European Academy of Dermatology and Venereology Mycology Task Force Malassezia folliculitis working group has, therefore, sought to develop these recommendations for the diagnosis and management of Malassezia folliculitis. Recommendations comprise methods for diagnosing Malassezia folliculitis, required positive findings before starting therapies and specific treatment algorithms for individuals who are immunocompetent, immunocompromised or who have compromised liver function. In conclusion, this study provides a clinical strategy for diagnosing and managing Malassezia folliculitis.

MALASSEZIA COLONIZATION CORRELATES WITH THE SEVERITY OF SEBORRHEIC DERMATITIS

OBJECTIVE

The aim: To compare the number of fungi of the genus Malassezia on inflated and healthy areas of the skin and to correlate them with the severity of seborrheic dermatitis.

PATIENTS AND METHODS

Materials and methods: 168 patients with typical manifestations of seborrheic dermatitis on the scalp and face and 30 healthy individuals were recruited. SD severity was assessed by SEDASI. Samples from lesions on scalp, face and intact chest skin were cultivated and/or stained with methylene blue or cotton and inoculated onto Malassezia Leeming & Notman Agar Modified (MLNA).

RESULTS

Results: A statistical difference in colonization intensity between all body zones (Dwass-Steel-Critchlow-Flinger pairwise comparisons p≤0,001). Face zone with lesions of SD patients was two times more colonized with funguses than in the control group (38,5 vs 16,5 p=0,003). The sternal area with no skin lesions was more colonized in the SD group (25,0 vs 9,0 p=0,013). The SEDASI was positively correlated with the amount of CFU on the face (Spearman's rho 0,849; p≤0,001) and trunk (0,714; p≤0,001).

CONCLUSION

Conclusions: Our results demonstrate that inflamed seborrheic areas are more colonized with Malassezia fungi than intact areas. The intensity of Malassezia growth is correlated with the severity of the symptoms of seborrheic dermatitis. The level of colonization may be a potential biomarker to indicate the efficiency of new treatment approaches.

Malassezia Folliculitis in the Setting of COVID-19

Purpose of Review

To review recent literature on Malassezia folliculitis and explore its association with COVID-19.

Recent Findings

Reports of Malassezia folliculitis in the setting of COVID-19 are scarce. Shared characteristics between affected individuals include male sex, obesity, intensive care, and administration of systemic antibiotics and systemic steroids. Dexamethasone can potentially stimulate sebum production and therefore lead to Malassezia proliferation. The clinical picture of Malassezia folliculitis accompanying COVID-19 is similar to classic descriptions but tends to spare the face and predominates in occlusion sites.

Summary

Malassezia folliculitis is under-recognized. Fever, sweating, occlusion, immobility, antibiotics, and dexamethasone contribute to COVID-19 patients developing Malassezia folliculitis. Antifungal therapy, together with correcting predisposing factors, is the mainstay of management. Future research should explore the relationship between systemic steroids and other acneiform reactions.