Comprehensive pyrosequencing analysis of the bacterial microbiota of the skin of patients with seborrheic dermatitis

Perturbations in the skin microbiome of infantile and adult seborrheic dermatitis and new treatment options based on restoring a healthy skin microbiome

Seborrheic dermatitis (SD) is a common, multifaceted skin condition, but its undefined etiology hampers the development of effective therapeutic strategies. In this review, we describe the intricate relationship between the skin microbiome and the pathogenesis of SD, focusing on the complex interplay between three major groups of organisms that can either induce inflammation (Malassezia spp., Staphylococcus aureus) or else promote healthy skin (Propionibacterium spp.). We describe how the disequilibrium of these microorganisms in the skin microbiome can develop skin inflammation in SD patients. Understanding these complex interactions of the skin microbiome has led to development of novel probiotics (e.g., Vitreoscilla spp. and Lactobacillus spp.) to restore normal skin physiology in SD. There are also differences in the skin microbiomes of healthy and SD infant and adult patients that impact pathogenesis and prompt different management strategies. A deeper understanding of the skin microbiome and its dynamic interactions will provide valuable insights into the pathogenesis of SD and prompt further development of targeted probiotic treatments to restore the balance of the skin microbiome in SD patients.

Unveiling the mechanism of essential oil action against skin pathogens: from ancient wisdom to modern science

Essential oils are among the most well-known phyto-compounds, and since ancient times, they have been utilized in medicine. Over 100 essential oils have been identified and utilized as therapies for various skin infections and related ailments. While numerous commercial medicines are available in different dosage forms to treat skin diseases, the persisting issues include their side effects, toxicity, and low efficacy. As a result, researchers are seeking novel classes of compounds as substitutes for synthetic drugs, aiming for minimal side effects, no toxicity, and high efficacy. Essential oils have shown promising antimicrobial activity against skin-associated pathogens. This review presents essential knowledge and scientific information regarding essential oil's antimicrobial capabilities against microorganisms that cause skin infections. Essential oils mechanisms against different pathogens have also been explored. Many essential oils exhibit promising activity against various microbes, which has been qualitatively assessed using the agar disc diffusion experiment, followed by determining the minimum inhibitory concentration for quantitative evaluation. It has been observed that Staphylococcus aureus and Candida albicans have been extensively researched in the context of skin-related infections and their antimicrobial activity, including established modes of action. In contrast, other skin pathogens such as Staphylococcus epidermidis, Streptococcus pyogens, Propionibacterium acnes, and Malassezia furfur have received less attention or neglected. This review report provides an updated understanding of the mechanisms of action of various essential oils with antimicrobial properties. This review explores the anti-infectious activity and mode of action of essential against distinct skin pathogens. Such knowledge can be valuable in treating skin infections and related ailments.

Microbiome: Role in Inflammatory Skin Diseases

As the body's largest organ, the skin harbors a highly diverse microbiota, playing a crucial role in resisting foreign pathogens, nurturing the immune system, and metabolizing natural products. The dysregulation of human skin microbiota is implicated in immune dysregulation and inflammatory responses. This review delineates the microbial alterations and immune dysregulation features in common Inflammatory Skin Diseases (ISDs) such as psoriasis, rosacea, atopic dermatitis(AD), seborrheic dermatitis(SD), diaper dermatitis(DD), and Malassezia folliculitis(MF).The skin microbiota, a complex and evolving community, undergoes changes in composition and function that can compromise the skin microbial barrier. These alterations induce water loss and abnormal lipid metabolism, contributing to the onset of ISDs. Additionally, microorganisms release toxins, like Staphylococcus aureus secreted α toxins and proteases, which may dissolve the stratum corneum, impairing skin barrier function and allowing entry into the bloodstream. Microbes entering the bloodstream activate molecular signals, leading to immune disorders and subsequent skin inflammatory responses. For instance, Malassezia stimulates dendritic cells(DCs) to release IL-12 and IL-23, differentiating into a Th17 cell population and producing proinflammatory mediators such as IL-17, IL-22, TNF-α, and IFN-α.This review offers new insights into the role of the human skin microbiota in ISDs, paving the way for future skin microbiome-specific targeted therapies.

Bacterial Skin Dysbiosis in Darier Disease

INTRODUCTION

Darier disease is a rare inherited disease with dominant skin manifestations including keratotic papules and plaques on sebaceous and flexural areas. Secondary infection of skin lesions is common, and Staphylococcus aureus commonly colonizes these lesions. The aim of the study was to characterize the bacterial microbiome of cutaneous Darier lesions compared to normal-looking skin and disease severity.

METHODS

All patients with a history of Darier followed up at Emek Medical Center were invited to participate in the study. Patients that did not use antibiotics in the past month and signed informed consent had four skin sites sampled with swabs: scalp, chest, axilla, and palm. All samples were analyzed for bacterial microbiome using 16S rDNA sequencing.

RESULTS

Two hundred and eighty microbiome samples obtained from lesional and non-lesional skin of the scalp, chest, axilla, and palm of 42 Darier patients were included in the analysis. The most abundant bacterial genera across all skin sites were Propionibacterium, Corynebacterium, Paracoccus, Micrococcus, and Anaerococcus. Scalp and chest lesions featured a distinct microbiome configuration that was mainly driven by an overabundance of Staphylococci species. Patients with more severe disease exhibited microbiome alterations in the chest, axilla, and palm compared with patients with only mild disease, driven by Peptoniphilus and Moryella genera in scalp and palmar lesions, respectively.

CONCLUSION

Staphylococci were significantly associated with Darier lesions and drove Darier-associated dysbiosis. Severity of the disease was associated with two other bacterial genera. Whether these associations also hold a causative role and may serve as a therapeutic target remains to be determined and requires further investigation.

Recent advances in understanding the role of the skin microbiome in the treatment of atopic dermatitis

The skin is the largest organ in the human body, and histologically consists of the epidermis, dermis and subcutaneous tissue. Humans maintain a cooperative symbiotic relationship with their skin microbiota, a complex community of bacteria, fungi and viruses that live on the surface of the skin, and which act as a barrier to protect the body from the inside and outside. The skin is a 'habitat' and vast 'ecosystem' inhabited by countless microbes; as such, relationships have been forged through millions of years of coevolution. It is not surprising then that microbes are key participants in shaping and maintaining essential physiological processes. In addition to maintaining barrier function, the unique symbiotic microbiota that colonizes the skin increases the immune response and provides protection against pathogenic microbes. This review examines our current understanding of skin microbes in shaping and enhancing the skin barrier, as well as skin microbiome-host interactions and their roles in skin diseases, such as atopic dermatitis (AD). We also report on the current status of AD therapeutic drugs that target the skin microbiome, related research on current therapeutic strategies, and the limitations and future considerations of skin microbiome research. In particular, as a future strategy, we discuss the need for a skin-on-a-chip-based microphysiological system research model amenable to biomimetic in vitro studies and human skin equivalent models, including skin appendages.

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.

Skin Microbiota and the Cosmetic Industry

Skin harbors an important microbial ecosystem - the skin microbiota that is in homeostasis with its host and is beneficial for human health. Cosmetic products have the potential to interfere with this microbial community; therefore their impact should be assessed. The aim of this review is to highlight the importance of skin microbiota in the cosmetic industry. Several studies determined that cosmetic ingredients have the potential to disrupt the skin microbiota equilibrium leading to the development of skin diseases and dysregulation of immune response. These studies led their investigation by using different methodologies and models, concluding that methods must be chosen according to the aim of the study, the skin site to be evaluated, and the target population of the cosmetics. Overall, it is crucial to test the impact of cosmetics in the skin microbiota and to stablish standard procedures, as well as specific criteria that allow to classify a cosmetic product as skin microbiota friendly.

Staphylococcus epidermidis and its dual lifestyle in skin health and infection

The coagulase-negative bacterium Staphylococcus epidermidis is a member of the human skin microbiota. S. epidermidis is not merely a passive resident on skin but actively primes the cutaneous immune response, maintains skin homeostasis and prevents opportunistic pathogens from causing disease via colonization resistance. However, it is now appreciated that S. epidermidis and its interactions with the host exist on a spectrum of potential pathogenicity derived from its high strain-level heterogeneity. S. epidermidis is the most common cause of implant-associated infections and is a canonical opportunistic biofilm former. Additional emerging evidence suggests that some strains of S. epidermidis may contribute to the pathogenesis of common skin diseases. Here, we highlight new developments in our understanding of S. epidermidis strain diversity, skin colonization dynamics and its multifaceted interactions with the host and other members of the skin microbiota.

Sodium hyaluronates applied in the face affects the diversity of skin microbiota in healthy people

OBJECTIVE

A healthy and stable microbiome has many beneficial effects on the host, while an unbalanced or disordered microbiome can lead to various skin diseases. Hyaluronic acid is widely used in the cosmetics and pharmaceutical industries; however, specific reports on its effect on the skin microflora of healthy people have not been published. This study aimed to determine the effect of sodium hyaluronate on the facial microflora of healthy individuals.

METHODS

Face of 20 healthy female volunteers between 18 and 24 years was smeared with sodium hyaluronate solution once per day. Cotton swabs were used to retrieve samples on days 0, 14, and 28, and high-throughput sequencing of 16 S rRNA was used to determine the changes in bacterial community composition.

RESULTS

Facial application of HA can reduce the abundance of pathogenic bacteria, such as Cutibacterium and S. aureus, and increase the colonization of beneficial bacteria.

CONCLUSION

This is the first intuitive report to demonstrate the effect of hyaluronic acid on facial microflora in healthy people. Accordingly, sodium hyaluronate was found to have a positive effect on facial skin health.

Analysis of cutaneous bacterial microbiota of Thai patients with seborrheic dermatitis

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition that occurs in body areas that contain profuse sebaceous glands. Skin microbiota are diverse across ethnic groups and its dysbiosis has been implicated in the pathogenesis of SD. Here, we reported the contribution of cutaneous bacterial microbiota to SD in the Thai population. Healthy individuals and patients with scalp SD were recruited into the study. Normal skin, scalp skin lesion (SL) and non-lesion sites (SNL) samples were collected using a tape stripping method and next-generation sequencing of 16S rRNA for microbiome analysis. Although bacterial diversity in all sample groups was not statistically different, a population of bacteria commonly found on skin of scalp showed signs of dysbiosis. Apart from the reduction of Corynebacterium spp., SD-specific microbiota was dominated by Firmicutes at taxa level and Pseudomonas spp., Staphylococcus spp. and Micrococcus spp. at genus level. The dysbiosis of the skin microbiota in SD was specifically described as an alteration of bacteria populations commonly found on scalp skin, implying that managing and controlling the cutaneous bacterial microbiome can alleviate and prevent SD and pave the way for the development of new SD treatments.

A Meta-Analysis on the Effectiveness of Sertaconazole 2% Cream Compared with Other Topical Therapies for Seborrheic Dermatitis

Seborrheic dermatitis (SD) is a relapsing inflammatory skin disorder that affects the seborrheic areas of the body. Its etiology is not completely elucidated; however, the link between disease exacerbations and the proliferation of Malassezia spp., along with the good response to antifungal agents, indicate the role of fungi in its pathophysiology. Sertaconazole nitrate is a relatively new imidazole antifungal agent with a particular structure, consisting in a benzothiophene ring similar to the indole ring of tryptophan, and it acts mainly through the inhibition of ergosterol synthesis and the formation of pores in the fungal cell membrane. The aim of our study was to evaluate the efficiency of sertaconazole 2% cream compared with other topical treatments in patients with SD. We performed an extensive literature search by browsing the PubMed database with the keyword combination “sertaconazole AND seborrheic dermatitis AND clinical trial”, which retrieved eight controlled clinical trials evaluating the effects of sertaconazole in SD. All of the clinical trials included a standard scoring index (SI). At 28 days since the beginning of the treatment, the sertaconazole regimen was associated with a significantly higher percentage of patients with mild SI and a lower percentage of patients with moderate or severe SI (odds ratio 0.51) than the other investigated treatments—hydrocortisone, ketoconazole, clotrimazole, metronidazole, pimecrolimus, and tacrolimus (odds ratio 1.95). In conclusion, treatment with sertaconazole 2% cream may represent an efficient alternative therapy for patients with SD.

Is cutaneous microbiota a player in disease pathogenesis? Comparison of cutaneous microbiota in psoriasis and seborrheic dermatitis with scalp involvement

BACKGROUND

Knowledge about cutaneous microbiota in psoriasis vulgaris and seborrheic dermatitis is limited, and a comparison of microbiota in the two diseases was not yet previously undertaken.

AIMS/OBJECTIVES

This study aimed to compare the scalp lesional and non-lesional microbiota in psoriasis vulgaris and seborrheic dermatitis with that in a healthy control group.

METHODS

Fifty samples were taken with sterile swabs from patients' and controls' scalps, and 16S rRNA gene sequencing analyses were performed.

RESULTS

Alpha and beta diversity analyses showed that bacterial load and diversity were significantly increased in psoriasis vulgaris and seborrheic dermatitis lesions compared to the controls. As phyla, Actinobacteria decreased and Firmicutes increased, while as genera, Propionibacterium decreased; Staphylococcus, Streptococcus, Aquabacterium, Neisseria and Azospirillum increased in lesions of both diseases. Specifically, Mycobacterium, Finegoldia, Haemophilus and Ezakiella increased in psoriasis vulgaris and Enhydrobacter, Micromonospora and Leptotrichia increased in seborrheic dermatitis lesions. Mycobacterium, Ezakiella and Peptoniphilus density were higher in psoriasis vulgaris compared to seborrheic dermatitis lesions. The bacterial diversity and load values of non-lesional scalp in psoriasis vulgaris and seborrheic dermatitis lay between those of lesional areas and controls.

LIMITATIONS

The small sample size is the main limitation of this study.

CONCLUSION

Higher bacterial diversity was detected in lesions of both psoriasis and seborrheic dermatitis compared to the controls, but similar alterations were observed when the two diseases were compared. Although these differences could be a result rather than a cause of the two diseases, there is a need to analyze all members of the microbiota and microbiota-host interactions.

The Human Skin Microbiome in Selected Cutaneous Diseases

The human skin harbors a wide variety of microbes that, together with their genetic information and host interactions, form the human skin microbiome. The role of the human microbiome in the development of various diseases has lately gained interest. According to several studies, changes in the cutaneous microbiota are involved in the pathophysiology of several dermatoses. A better delineation of the human microbiome and its interactions with the innate and adaptive immune systems could lead to a better understanding of these diseases, as well as the opportunity to achieve new therapeutic modalities. The present review centers on the most recent knowledge on skin microbiome and its participation in the pathogenesis of several skin disorders: atopic and seborrheic dermatitis, alopecia areata, psoriasis and acne.

Evaluation of a new-formula shampoo containing 6% glycyrrhetinic acid complex for scalp seborrheic dermatitis: A pilot study

Background

Scalp seborrheic dermatitis (SD) is a chronic inflammatory dermatosis associated with sebum imbalance and proliferation of Malassezia species. Various antifungal shampoos are commonly used for scalp SD.

Aims

Glycyrrhetinic acid is known to have antioxidative, anti‐inflammatory, and anti‐allergic effects. This study was designed to evaluate the effectiveness of a new‐formula shampoo that contains glycyrrhetinic acid for the treatment of scalp SD.

Patients/Methods

Thirty‐four patients were enrolled and treated with the 6% glycyrrhetinic acid complex shampoo. Efficacy was assessed clinically with Dermatology Life Quality Index (DLQI) and Adherent Scalp Flaking Score (ASFS) by the same dermatologist at baseline, week 2, and week 5. Among the 24 subjects with the most significant clinical improvement, four common microorganisms from scalp samples were analyzed by quantitative polymerase chain reaction (qPCR) at baseline, and week 5.

Results

The DLQI and ASFS at week 2 and week 5 improved significantly relative to baseline. The bacteria profiles showed a significant increase of Cutibacterium acnes and a decrease of Staphylococcus epidermidis at week 5. The fungi profiles showed significant decreases of both Malassezia restricta and Malassezia globosa. The ratio of C. acne to S. epidermidis increased significantly from 0.93 at baseline to 1.55 at week 5. The ratio of M. restricta to M. globosa decreased from 5.02 at baseline to 1.00 at week 5.

Conclusions

The effectiveness of this new regimen was objectively demonstrated at the clinical and microbiological levels. This new formula may alleviate the bacterial and fungal dysbiosis in scalp SD.

Hallazgos en piel en pacientes con infección por VIH en Bogotá

Objetivo Describir los hallazgos en piel y las características sociodemográficas de pacientes VIH positivos atendidos en un centro de remisión en Bogotá. Métodos Se realizó un estudio observacional descriptivo, incluyendo adultos con infección por VIH atendidos en el Hospital Universitario San Ignacio de Bogotá, entre abril de 2019 y febrero de 2020. A partir de un interrogatorio, un examen físico y la revisión de historias clínicas, se registraron hallazgos en piel, datos de terapia antirre- troviral recibida, conteo de linfocitos CD4+ y carga viral para VIH, así como pruebasmicológicas e histopatológicas (cuando fueron necesarias). Resultados Se evaluó un total de 168 pacientes que, en su mayoría, eran hombres (88,7%), en la cuarta década de la vida, de orientación HSH (77,4%), con fototipos del II al IV (97%) y manejados con terapia antirretroviral (94,6%). Se encontraron hallazgos en piel en el 97,6% de los pacientes, siendo más frecuentes las infecciones (43,8%), específicamente los condilomas anogenitales, principalmente en pacientes con <200 linfocitos CD4+/mm3, seguidas por las condiciones inflamatorias (35,4%), principalmente dermatitis seborreica y acné. Este último, más frecuente en pacientes con >200 linfocitos CD4+/mm3. Conclusiones Los hallazgos más frecuentes en piel fueron: dermatitis seborreica, condilomas anogenitales, verrugas virales, moluscos contagiosos y micosis superficiales, que se asemeja a lo reportado en poblaciones con buen control inmunovirológico de la enfermedad. La alta prevalencia de condilomas anogenitales nos invita a imple- mentar estrategias de tamización para VPH, así como de educación en infecciones de transmisión sexual.

Differences in the skin microbial community between patients with active and stable vitiligo based on 16S rRNA gene sequencing

BACKGROUND/OBJECTIVE

Recent studies have described an association between altered skin microbial community and epidemiology of skin diseases, such as vitiligo, atopic dermatitis and psoriasis. In this study, we conducted microbiological analysis on patients at different stages of vitiligo to determine whether the dysbiosis is associated with disease progression.

METHODS

To characterise the skin microbes in vitiligo patients, we profiled samples collected from 40 patients with active and stable vitiligo using the Novaseq sequencer. Alpha diversity was used to measure richness and uniformity, while Beta diversity (Non-Metric Multi-Dimensional Scaling) analysis was used to show the differences. Moreover, the species differences were evaluated by LEfSe analysis and the flora gene function was predicted using Statistical Analysis of Metagenomic Profiles (STAMP).

RESULTS

The alpha diversity results showed no significant differences between active vitiligo and stable vitiligo, while beta diversity and LEfSe analysis results showed the differences in community composition. Streptomyces and Streptococcus were enriched in active vitiligo compared to stable vitiligo. In addition, the flora gene function of mixed acid fermentation was more pronounced in active vitiligo, while the function of lipid IVA biosynthesis was more significant in stable vitiligo.

CONCLUSION

This study has shown the differences in epidermal microbes between active vitiligo and stable vitiligo. Our results suggest that maintaining the flora balance might be a potential therapeutic target for vitiligo.

Features of the Skin Microbiota in Common Inflammatory Skin Diseases

Many relatively common chronic inflammatory skin diseases manifest on the face (seborrheic dermatitis, rosacea, acne, perioral/periorificial dermatitis, periocular dermatitis, etc.), thereby significantly impairing patient appearance and quality of life. Given the yet unexplained pathogenesis and numerous factors involved, these diseases often present therapeutic challenges. The term “microbiome” comprises the totality of microorganisms (microbiota), their genomes, and environmental factors in a particular environment. Changes in human skin microbiota composition and/or functionality are believed to trigger immune dysregulation, and consequently an inflammatory response, thereby playing a potentially significant role in the clinical manifestations and treatment of these diseases. Although cultivation methods have traditionally been used in studies of bacterial microbiome species, a large number of bacterial strains cannot be grown in the laboratory. Since standard culture-dependent methods detect fewer than 1% of all bacterial species, a metagenomic approach could be used to detect bacteria that cannot be cultivated. The skin microbiome exhibits spatial distribution associated with the microenvironment (sebaceous, moist, and dry areas). However, although disturbance of the skin microbiome can lead to a number of pathological conditions and diseases, it is still not clear whether skin diseases result from change in the microbiome or cause such a change. Thus far, the skin microbiome has been studied in atopic dermatitis, seborrheic dermatitis, psoriasis, acne, and rosacea. Studies on the possible association between changes in the microbiome and their association with skin diseases have improved the understanding of disease development, diagnostics, and therapeutics. The identification of the bacterial markers associated with particular inflammatory skin diseases would significantly accelerate the diagnostics and reduce treatment costs. Microbiota research and determination could facilitate the identification of potential causes of skin diseases that cannot be detected by simpler methods, thereby contributing to the design and development of more effective therapies.

Skin microbiome alterations in seborrheic dermatitis and dandruff: A systematic review

Seborrheic dermatitis (SD) and dandruff (DF) are common chronic inflammatory skin diseases characterized by recurrent greasy scales, sometimes with erythema and itchiness. Although the exact pathophysiology of the disease is still unclear, current theories highlight the role of microbes on the skin surface in the pathogenesis of SD. Here, we conducted a systematic review to investigate the skin microbiome alterations in patients with SD/DF. We searched Medline/PubMed, Embase and Web of Science for research studies published in English between 1 January 2000 and 31 December 2020. A total of 12 studies with 706 SD/DF samples and 379 healthy samples were included in this study. The scalp and face were predominated by the fungi of Ascomycota and Basidiomycota and the bacteria of Actinobacteria and Firmicutes. In general, the included studies demonstrated an increased Malassezia restricta/Malassezia globosa ratio and a reduction in the Cutibaterium/Staphylococcus ratio in the setting of SD/DF. Staphylococcus was associated with epidermal barrier damage, including elevated levels of trans-epidermal water loss and pH, while Cutibacterium had a positive correlation with water content. Malassezia was also found to be related to an increased itching score and disease severity. Further studies focusing on the interactions between various microbes and the host and microbes can help us to better understand the pathogenesis of SD/DF.

Continuous clinical improvement of mild-to-moderate seborrheic dermatitis and rebalancing of the scalp microbiome using a selenium disulfide-based shampoo after an initial treatment with ketoconazole

OBJECTIVE

Scalp seborrheic dermatitis (SD) is a chronic, relapsing, and inflammatory scalp disease. Studies indicate a global bacterial and fungal microbiota shift of scalp SD, as compared to healthy scalp. Ketoconazole and selenium disulfide (SeS₂ ) improve clinical signs and symptoms in both scalp dandruff and SD.

AIM

The main objective of this study was to investigate the changes in the scalp microbiota diversity and counts in subjects with scalp SD during a two-phase treatment period.

MATERIAL AND METHODS

The scalp microbiota and clinical efficacy were investigated in 68 subjects with mild-to-moderate scalp SD after an initial one-month treatment with 2% ketoconazole, and after a 2-month maintenance phase, either with a 1% SeS₂ -based shampoo or its vehicle.

RESULTS

Thirty one subjects in the active and 37 subjects in the vehicle group participated. Ketoconazole provided an improvement of clinical symptoms (adherent (-1.75 p < 0.05), non-adherent (-1.5, p < 0.05)) flakes and erythema (scores 1.67-0.93, p < 0.001), in an increased fungal diversity and in a significant (p < 0.005) decrease of Malassezia spp. SeS₂ provided an additional clinical improvement (-0.8; p = 0.0002 and -0.7; p = 0.0081 for adherent and non-adherent flakes, respectively, at Day 84) compared to the vehicle associated with a low Malassezia spp. count and an additional significant (p < 0.001) decrease of the Staphylococcus spp. level.

CONCLUSION

Selenium disulfide provides an additional benefit on the scalp microbiota and in clinical symptoms of SD and dandruff after treatment with ketoconazole. The results confirm the role of Staphylococcus spp. in scalp SD and open possible perspectives for preventing relapses.

Challenges in exploring and manipulating the human skin microbiome

The skin is the exterior interface of the human body with the environment. Despite its harsh physical landscape, the skin is colonized by diverse commensal microbes. In this review, we discuss recent insights into skin microbial populations, including their composition and role in health and disease and their modulation by intrinsic and extrinsic factors, with a focus on the pathobiological basis of skin aging. We also describe the most recent tools for investigating the skin microbiota composition and microbe-skin relationships and perspectives regarding the challenges of skin microbiome manipulation. Video abstract.

Composition of cutaneous bacterial microbiome in seborrheic dermatitis patients: A cross-sectional study

Background

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease with a multifactorial aetiology. Malassezia yeasts have been associated with the disease but the role of bacterial composition in SD has not been thoroughly investigated.

Objectives

To profile the bacterial microbiome of SD patients and compare this with the microbiome of individuals with no inflammatory skin disease (controls).

Methods

This was a cross sectional study embedded in a population-based study. Skin swabs were taken from naso-labial fold from patients with seborrheic dermatitis (lesional skin: n = 22; non-lesional skin SD: n = 75) and controls (n = 465). Sample collection began in 2016 at the research facility and is still ongoing. Shannon and Chao1 α- diversity metrics were calculated per group. Associations between the microbiome composition of cases and controls was calculated using multivariate statistics (permANOVA) and univariate statistics.

Results

We found an increased α-diversity between SD lesional cases versus controls (Shannon diversity: Kruskal-Wallis rank sum: Chi-squared: 19.06; global p-value = 7.7x10^-5). Multivariate statistical analysis showed significant associations in microbiome composition when comparing lesional SD skin to controls (p-value = 0.03;R² = 0.1%). Seven out of 13 amplicon sequence variants (ASVs) that were significantly different between controls and lesional cases were members of the genus Staphylococcus, most of which showed increased composition in lesional cases, and were closely related to S. capitis S. caprae and S. epidermidis.

Conclusion

Microbiome composition differs in patients with seborrheic dermatitis and individuals without diseases. Differences were mainly found in the genus Staphylococcus.

Treatment of cradle cap in infants with a new cosmetic non-steroidal gel cream: Clinical, laboratory, and instrumental evaluation

Background

Cradle cap is a benign and self‐limiting variant of seborrheic dermatitis (SD) that can be distressing for parents.

Aims

To assess by clinical/laboratory/instrumental evaluation the efficacy/tolerability of a gel cream containing piroctone olamine (antifungal), biosaccharide gum‐2 (antifungal), stearyl glycyrrhetinate (anti‐inflammatory), and zinc l‐pyrrolidone carboxylate (zinc‐PCA) (antiseborrheic) in the treatment of mild/ moderate cradle cap.

Methods

In this prospective, open‐label trial, 10 infants, with mild/moderate cradle cap enrolled at the Dermatology University Clinic of Catania (Italy) used the tested gel cream twice daily for 30 days. Degree of erythema was evaluated clinically by a 5‐point severity scale (from 0=no erythema to 4=severe erythema), at baseline, at 15 and 30 days. Desquamation was rated by dermoscopy evaluation using a 5‐point scale (from 0=no desquamation to 4=severe/many large adherent white flakes), at all time points. An Investigator Global Assessment (IGA) using a 6‐point scale (from −1=worsening to 4=complete response/clear) was also performed at 30 days. Five subjects, randomly selected, underwent double microbiological evaluation for bacteria and yeasts by cultures of cotton swabs at baseline and at 30 days. Tolerability/acceptability was evaluated on a 4‐point scale (from 0=very poor to 3=excellent) at 15 and 30 days. Data were processed using SAS version 9.

Results

At baseline, a significant colony‐forming unit (CFU) count for Malassezia furfur and Staphylococcus aureus was detected in 4 out of 5 selected patients. After 15 and 30 days, a statically significant reduction from baseline in erythema and desquamation severity was observed, along with a reduction in CFU count for Malassezia furfur and Staphylococcus aureus from baseline. No signs of local side effects were documented.

Conclusions

Our results indicate that the tested gel cream may represent a valid option to treat mild‐to‐moderate forms of cradle cap and support its antifungal and antibacterial properties.

Longitudinal study of the scalp microbiome suggests coconut oil to enrich healthy scalp commensals

Dandruff is a recurrent chronic scalp disorder, affecting majority of the population worldwide. Recently a metagenomic study of the Indian scalp microbiome described an imperative role of bacterial commensals in providing essential vitamins and amino acids to the scalp. Coconut oil and its formulations are commonly applied on the scalp in several parts of the world to maintain scalp health. Thus, in this study we examined the effect of topical application of coconut oil on the scalp microbiome (bacterial and fungal) at the taxonomic and functional levels and their correlation with scalp physiological parameters. A 16-weeks-long time-course study was performed including 12-weeks of treatment and 4-weeks of relapse phase on a cohort of 140 (70 healthy and 70 dandruff) Indian women, resulting in ~ 900 metagenomic samples. After the treatment phase, an increase in the abundance of Cutibacterium acnes and Malassezia globosa in dandruff scalp was observed, which were negatively correlated to dandruff parameters. At the functional level, an enrichment of healthy scalp-related bacterial pathways, such as biotin metabolism and decrease in the fungal pathogenesis pathways was observed. The study provides novel insights on the effect of coconut oil in maintaining a healthy scalp and in modulating the scalp microbiome.

Amplicon-based skin microbiome profiles collected by tape stripping with different adhesive film dressings: a comparative study

Background

Medical film dressings have been used to obtain skin microbiota for skin microbiome studies, although their adhesive force may be so strong that the skin could be injured when applied to those who have fragile skin, such as older people. Several products with less adhesive force are available, although their applicability for skin microbiome studies remains unknown. This study aimed to test whether the dressings with less adhesive force could be used for amplicon-based skin microbiome studies. A set of three different film dressings, with acrylic, urethane, or silicone adhesive, was applied to the back skin of nine healthy young participants. The copy number of the 16S ribosomal RNA (rRNA) gene, microbial compositions, and alpha and beta diversity indices were analyzed by amplicon analysis of the 16S rRNA gene using next-generation sequencing and were compared among the three film dressings.

Results

The dressing with acrylic adhesive yielded the highest copy number of 16S rRNA genes, followed by that with urethane adhesive. The silicone-adhesive dressing yielded a significantly lower copy number of the 16S rRNA gene. The microbial composition of skin microbiota was similar among the three film dressings, although significant differences in the relative abundance of Pseudomonas species and alpha diversity indices were found in the silicone-adhesive dressing. The Bray–Curtis dissimilarity was significantly higher between the acrylic- and silicone-adhesive dressings than between the acrylic- and urethane-adhesive dressings. No adverse effects related to tape stripping were observed for any of the film dressings.

Conclusion

We recommend dressings with acrylic or urethane adhesive for amplicon-based skin microbiome studies. An acrylic adhesive has an advantage in the yield of skin microbiota, and a urethane adhesive should be chosen when applied to fragile skin. The adhesive force of the dressing with silicone adhesive was too weak to be used for collecting skin microbiota.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02122-4.

Consensus on the use of oral isotretinoin in dermatology - Brazilian Society of Dermatology

BACKGROUND

Isotretinoin is a synthetic retinoid, derived from vitamin A, with multiple mechanisms of action and highly effective in the treatment of acne, despite common adverse events, manageable and dose-dependent. Dose-independent teratogenicity is the most serious. Therefore, off-label prescriptions require strict criteria.

OBJECTIVE

To communicate the experience and recommendation of Brazilian dermatologists on oral use of the drug in dermatology.

METHODS

Eight experts from five universities were appointed by the Brazilian Society of Dermatology to develop a consensus on indications for this drug. Through the adapted DELPHI methodology, relevant elements were listed and an extensive analysis of the literature was carried out. The consensus was defined with the approval of at least 70% of the experts.

RESULTS

With 100% approval from the authors, there was no doubt about the efficacy of oral isotretinoin in the treatment of acne, including as an adjunct in the correction of scars. Common and manageable common adverse events are mucocutaneous in nature. Others, such as growth retardation, abnormal healing, depression, and inflammatory bowel disease have been thoroughly investigated, and there is no evidence of a causal association; they are rare, individual, and should not contraindicate the use of the drug. Regarding unapproved indications, it may represent an option in cases of refractory rosacea, severe seborrheic dermatitis, stabilization of field cancerization with advanced photoaging and, although incipient, frontal fibrosing alopecia. For keratinization disorders, acitretin performs better. In the opinion of the authors, indications for purely esthetic purposes or oil control are not recommended, particularly for women of childbearing age.

CONCLUSIONS

Approved and non-approved indications, efficacy and adverse effects of oral isotretinoin in dermatology were presented and critically evaluated.

Potential role of the skin microbiota in Inflammatory skin diseases

BACKGROUND

Inflammatory skin diseases include a variety of skin diseases, such as seborrheic dermatitis, acne, atopic dermatitis, psoriasis and so on, which are more common and tend to have a significant impact on patients' quality of life. Inflammatory skin diseases often result in physical or psychological distress; however, the pathogenesis of these diseases have not been clearly elucidated. Many factors are involved in the pathogenesis of inflammatory skin diseases, including heredity, environment, immunity, epidermal barrier, mental disorders, infection and so on. In recent years, skin microbiota has been shown to play an important role in inflammatory skin diseases.

AIMS

To elaborate on the specific mechanisms of inflammatory skin diseases induced by microbiota dysbiosis.

METHODS

We introduce the function and influence of skin microbiota in inflammatory skin diseases from the following aspects: Immunity, epigenetics, epidermal barrier and treatment.

RESULTS

Skin microbiota can affect many aspects of the host, such as Immunity, epigenetics, epidermal barrier, and it plays an important role in the pathogenesis of inflammatory skin diseases.

CONCLUSION

Skin microbiota is extremely important for maintaining the health of skin and the dysbiosis of skin microbiota is an important pathogenesis of inflammatory skin diseases.

Scalp microbiota in members of a Japanese high school judo team including Trichophyton tonsurans carriers

Trichophyton tonsurans is a major causative fungus of human dermatophytosis, which has been isolated from contact sport players in Japan. The microbiome in the scalp of judoists with or without T. tonsurans infection was analyzed to investigate the correlation between T. tonsurans infection and microbiome profile. Among 30 members of the same judo team in a high school, samples were collected by scrubbing their scalp with shampoo hairbrushes; then, DNA was extracted directly from the obtained scales. Twenty-seven datasets were subjects for microbiome analysis and T. tonsurans was detected in six members (no T. tonsurans-positive participants had scalp lesions). Regarding the fungal microbiome, Cyphellophora were more abundant in the T. tonsurans-positive group (TP) than T. tonsurans-negative group (TN) (P < 0.05). Regarding the Malassezia microbiome, Malassezia caprae were more abundant in TP than TN (P < 0.01). Regarding the bacterial microbiome, Lactococcus, Actinobacillus, Beijerinckiaceae and Xanthomonas were more abundant in TP than TN (P < 0.05). Also, the Shannon diversity index revealed no significant diversity between TP and TN, and 3-D principal coordinate analysis revealed no clear separation between TP and TN. There was practically no difference in microbiome between TP and TN, indicating that T. tonsurans could colonize humans regardless of their original microbiome. T. tonsurans coexisted with other fungi and bacteria without affecting species diversity in asymptomatic carriers. To our knowledge, this is the first investigation of the correlation between T. tonsurans infection and microbiome profile.

Feasibility of microbial sample collection on the skin from people in Yaoundé, Cameroon

Characterization of microbial communities in the skin in healthy individuals and diseased patients holds valuable information for understanding pathogenesis of skin diseases and as a source for developing novel therapies. Notably, resources regarding skin microbiome are limited in developing countries where skin disorders from infectious diseases are extremely common. A simple method for sample collection and processing for skin microbiome studies in such countries is crucial. The aim of this study is to confirm the feasibility of collecting skin microbiota from individuals in Yaoundé, a capital city of Cameroon, and subsequent extraction of bacterial DNA in a resource limited setting. Skin swabs from several individuals in Yaoundé were successfully obtained, and sufficient amount of bacterial 16S ribosomal RNA-coding DNA was collected, which was confirmed by quantitative PCR. The median copy number of 16S ribosomal RNA gene varied across participants and collection sites, with significantly more copies in samples collected from the forehead compared to the left and right forearm, or back. This study demonstrated that collecting surface skin microbes using our swabbing method is feasible in a developing country. We further showed that even with limited resources, we could collect sufficient amount of skin microbiota from the inhabitants in Yaoundé where no studies of skin microbiome were reported, which can be passed to further metagenomic analysis such as next generation sequencing.

An update on the microbiology, immunology and genetics of seborrheic dermatitis

The underlying mechanism of seborrheic dermatitis (SD) is poorly understood but major scientific progress has been made in recent years related to microbiology, immunology and genetics. In light of this, the major goal of this article was to summarize the most recent articles on SD, specifically related to underlying pathophysiology. SD results from Malassezia hydrolysation of free fatty acids with activation of the immune system by the way of pattern recognition receptors, inflammasome, IL-1β and NF-kB. M. restricta and M. globosa are likely the most virulent subspecies, producing large quantities of irritating oleic acids, leading to IL-8 and IL-17 activation. IL-17 and IL-4 might play a big role in pathogenesis, but this needs to be further studied using novel biologics. No clear genetic predisposition has been established; however, recent studies implicated certain increased-risk human leucocyte antigen (HLA) alleles, such as A*32, DQB1*05 and DRB1*01 as well as possible associations with psoriasis and atopic dermatitis (AD) through the LCE3 gene cluster while SD, and SD-like syndromes, shares genetic mutations that appear to impair the ability of the immune system to restrict Malassezia growth, partially due to complement system dysfunction. A paucity of studies exists looking at the relationship between SD and systemic disease. In HIV, SD is thought to be secondary to a combination of immune dysregulation and disruption in skin microbiota with unhindered Malassezia proliferation. In Parkinson's disease, SD is most likely secondary to parasympathetic hyperactivity with increased sebum production as well as facial immobility which leads to sebum accumulation.

Malassezia and Staphylococcus dominate scalp microbiome for seborrheic dermatitis

Seborrheic dermatitis (SD) is a common disease of the human scalp that causes physical damage and psychological problems for patients. Studies have indicated that dysbiosis of the scalp microbiome results in SD. However, the specific fungal and bacterial microbiome changes related to SD remain elusive. To further investigate the fungal and bacterial microbiome changes associated with SD, we recruited 57 SD patients and 53 healthy individuals and explored their scalp microbiomes using next generation sequencing and the QIIME and LEfSe bioinformatics tools. Skin pH, sebum secretion, hydration, and trans-epidermal water loss (TWEL) were also measured at the scalp. We found no statistically significant differences between the normal and lesion sites in SD patients with different subtypes of dandruff and erythema. However, the fungal and bacterial microbiome could differentiate SD patients from healthy controls. The presence of Malassezia and Aspergillus was both found to be potential fungal biomarkers for SD, while Staphylococcus and Pseudomonas were found to be potential bacterial biomarkers. The fungal and bacterial microbiome were divided into three clusters through co-abundance analysis and their correlations with host factors indicated the interactions and potential cooperation and resistance between microbe communities and host. Our research showed the skin microbe dysbiosis of SD and highlighted specific microorganisms that may serve as potential biomarkers of SD. The etiology of SD is multi-pathogenetic-dependent on the linkage of several microbes with host. Scalp microbiome homeostasis could be a promising new target in the risk assessment, prevention, and treatment of SD disease.

Exploring Anti-Fungal, Anti-Microbial and Anti-Inflammatory Properties of a Topical Non-Steroidal Barrier Cream in Face and Chest Seborrheic Dermatitis

INTRODUCTION

The pathogenesis of seborrheic dermatitis (SD) is multifactorial and traditional treatments may not target all aspects of it. The aim of this study was to evaluate short-term anti-fungal, anti-microbial, anti-inflammatory and anti-pruritus properties of a novel non-steroidal cream (NSC) containing piroctone olamine, zinc salt of L-pyrrolidone carboxylate (PCA), hydroxyphenyl propamidobenzoic acid, biosaccharide gum-2 and stearyl glycyrrhetinate in patients with face and chest SD.

METHODS

Twelve male subjects affected by SD, presenting face and chest manifestations, were enrolled. Patients were instructed to apply NSC twice a day, performing regular visits at baseline (W0), after 7 (W1) and 14 (W2) days of treatment. A limitation of the study was that no control group treated with the vehicle without active ingredients was enrolled. To evaluate the efficacy of the NSC, investigator's assessments were represented by scoring index (SI) and investigator's global assessment score (IGA). In order to assess NSC anti-fungal and anti-microbial effects, skin scale scrapings were collected and used for Malassezia furfur (MF) and Staphylococcus epidermidis (SE) cultures. In parallel, in order to assess NSC anti-inflammatory effects, gene expression of IL-1α, IL-1β, IL-6, IL-8, and TNF-α was assessed. In addition, anti-pruritus effects were also evaluated through gene expression of cathepsin S and L-histidine decarboxylase.

RESULTS

SI mean scores significantly decreased at W1 and, to a greater extent, at W2 compared with W0. The IGA score registered an important improvement efficacy both for face and chest, from W1 to W2. MF and SE growth was already inhibited at W1, with a more pronounced decrease at W2. Gene expression of all analyzed mediators was significantly reduced at W1 compared to W0.

CONCLUSION

In conclusion, our assessment is that NSC is an effective and well tolerated treatment option for SD with anti-fungal, anti-microbial and anti-inflammatory properties.

TRIAL REGISTRATION

ISRCTN registry, ISRCTN77871064 (retrospectively registered October 17, 2019). EudraCT number, 2019-003813-32.

FUNDING

ISDIN.

The Skin and Gut Microbiome and Its Role in Common Dermatologic Conditions

Microorganisms inhabit various areas of the body, including the gut and skin, and are important in maintaining homeostasis. Changes to the normal microflora due to genetic or environmental factors can contribute to the development of various disease states. In this review, we will discuss the relationship between the gut and skin microbiome and various dermatological diseases including acne, psoriasis, rosacea, and atopic dermatitis. In addition, we will discuss the impact of treatment on the microbiome and the role of probiotics.

Isolation of Malassezia spp. in HIV-positive patients with and without seborrheic dermatitis

Background

Malassezia, a skin saprophyte, is frequently isolated from patients with seborrheic dermatitis, which is one of the most common dermatoses in HIV-infected patients. Its role in pathophysiology has not been defined.

Objective

To determine whether patients living with HIV and seborrheic dermatitis have more Malassezia than those without seborrheic dermatitis.

Method

This is an descriptive, observational, prospective cross-sectional study to which all adult patients living with HIV that attend the infectious disease outpatient clinic at the Dr. Manuel Gea González General Hospital were invited. Patients presenting with scale and erythema were included in Group 1, while patients without erythema were included in Group 2. Samples were taken from all patients for smear and culture.

Results

Thirty patients were included in each group. All patients with seborrheic dermatitis had a positive smear, with varying amounts of yeasts. In the control group, 36.7% of patients had a negative smear. The results are statistically significant, as well as the number of colonies in the cultures.

Study limitations The study used a small sample size and the subspecies were not identified.

Conclusions

Patients with clinical manifestations of seborrheic dermatitis have larger amounts of Malassezia. Further studies need to be performed to analyze if the greater amount is related to imbalances in the microbiota of the skin.

The infantile cutaneous microbiome: A review

Recent focus on the neonatal intestinal microbiome has advanced our knowledge of the complex interplay between the intestinal barrier, the developing immune system, and commensal and pathogenic organisms. Despite the parallel role of the infant skin in serving as both a barrier and an interface for priming the immune system, large gaps exist in our understanding of the infantile cutaneous microbiome. The skin microbiome changes and matures throughout infancy, becoming more diverse and developing the site specificity known to exist in adults. Delivery method initially determines the composition of the cutaneous microbiome, though this impact appears transient. Cutaneous microbes play a critical role in immune system development, particularly during the neonatal period, and microbes and immune cells have closely intertwined, reciprocal effects. The unique structure of newborn skin influences cutaneous microbial colonization and the development of dermatologic pathology. The development of the infantile skin barrier and cutaneous microbiome contributes to future skin pathology. Atopic dermatitis flares and seborrheic dermatitis have been linked to dysbiosis, while erythema toxicum neonatorum is an immune response to the establishment of normal bacterial skin flora. Physicians who care for infants should be aware of the impact of the infantile skin microbiome and its role in the development of pathology. A better understanding of the origin and evolution of the skin microbiome will lead to more effective prevention and treatment of pediatric skin disease.

Changing our microbiome: probiotics in dermatology

BACKGROUND

Commensal bacteria are a major factor in human health and disease pathogenesis. Interest has recently expanded beyond the gastrointestinal microbiome to include the skin microbiome and its impact on various skin diseases.

OBJECTIVES

Here we present current data reviewing the role of the microbiome in dermatology, considering both the gut and skin microflora. Our objective was to evaluate whether the clinical data support the utility of oral and topical probiotics for certain dermatological diseases.

METHODS

The PubMed and ClinicalTrials.gov databases were searched for basic science, translational research and clinical studies that investigated differences in the cutaneous microbiome and the impact of probiotics in patients with atopic dermatitis, acne vulgaris, psoriasis, chronic wounds, seborrhoeic dermatitis and cutaneous neoplasms.

RESULTS

Few clinical trials exist that explore the utility of probiotics for the prevention and treatment of dermatological diseases, with the exception of atopic dermatitis. Most studies investigated oral probiotic interventions, and of those utilizing topical probiotics, few included skin commensals. In general, the available clinical trials yielded positive results with improvement of the skin conditions after probiotic intervention.

CONCLUSIONS

Oral and topical probiotics appear to be effective for the treatment of certain inflammatory skin diseases and demonstrate a promising role in wound healing and skin cancer. However, more studies are needed to confirm these results. What's already known about this topic? The microbiome plays a role in human health and disease pathogenesis. Probiotics can manipulate the host microbiome and may confer health benefits for patients. Research to date has already begun to explore the utility of oral and topical probiotics for certain dermatological diseases. What does this study add? This review presents basic science and clinical trial data to support the role of the gut and skin microbiome in dermatology. Current data are reviewed on the use of probiotics in the prevention and treatment of skin diseases, including atopic dermatitis, acne vulgaris, psoriasis, seborrhoeic dermatitis, chronic wounds and cutaneous neoplasms. Future probiotic interventions are proposed.

Microbiome in the hair follicle of androgenetic alopecia patients

Androgenetic alopecia is the most common form of hair loss in males. It is a multifactorial condition involving genetic predisposition and hormonal changes. The role of microflora during hair loss remains to be understood. We therefore analyzed the microbiome of hair follicles from hair loss patients and the healthy. Hair follicles were extracted from occipital and vertex region of hair loss patients and healthy volunteers and further dissected into middle and lower compartments. The microbiome was then characterized by 16S rRNA sequencing. Distinct microbial population were found in the middle and lower compartment of hair follicles. Middle hair compartment was predominated by Burkholderia spp. and less diverse; while higher bacterial diversity was observed in the lower hair portion. Occipital and vertex hair follicles did not show significant differences. In hair loss patients, miniaturized vertex hair houses elevated Propionibacterium acnes in the middle and lower compartments while non-miniaturized hair of other regions were comparable to the healthy. Increased abundance of P. acnes in miniaturized hair follicles could be associated to elevated immune response gene expression in the hair follicle.

Effects of a cream containing 5% hyaluronic acid mixed with a bacterial-wall-derived glycoprotein, glycyrretinic acid, piroctone olamine and climbazole on signs, symptoms and skin bacterial microbiota in subjects with seborrheic dermatitis of the face

Objective: A new cream formulation containing hyaluronic acid 5%, complexed with a mix of a bacterial-wall-derived glycoprotein and peptide glycan complex (EDS), has been recently developed. We evaluated in a prospective, assessor-blinded, 6-week study the efficacy and tolerability of EDS in the treatment of facial seborrheic dermatitis (SD) and the effects on skin microbiota.

Subjects and methods: Seventy-five subjects (mean age 46; 60 men) with moderate-severe SD of the face were enrolled. EDS cream was applied twice daily. The primary outcome was the evolution of the Investigator Global Assessment (IGA) score, evaluating erythema, scale/flaking, grade of seborrhea and itch. Superficial skin bacterial microbiome at baseline and after treatment was assessed, using the 16S rRNA gene methodology, in affected and non-affected face areas. Local tolerability was evaluated checking self-reported side effects at each visit.

Results: Baseline IGA scores (mean±SD) was 10±3. The use of EDS reduced IGA score significantly by 70% at week 3 and by 88% at week 6. An increase in the abundance of Cutibacterium acnes genera associated with a significant drop of Staphylococcus genera presence was detected in affected areas. The ratio of relative abundance of genera Cutibacterium/Staphylococcus increased significantly after treatment in affected areas. The product was very well tolerated.

Conclusion: Treatment with EDS applied twice daily for 6 consecutive weeks was associated with a reduction of the signs and symptoms of SD. Furthermore, after EDS cream treatment, a reequilibrating effect on facial skin microbiota was observed. The product was very well tolerated.

Neutral Processes Drive Seasonal Assembly of the Skin Mycobiome

The importance of microorganisms to human skin health has led to a growing interest in the temporal stability of skin microbiota. Here we investigated the dynamics and assembly of skin fungal communities (mycobiomes) with amplicon sequencing of samples collected from multiple sites on 24 healthy Chinese individuals across four seasons (in the order of winter, spring, summer, and autumn in a calendar year). We found a significant difference in community compositions between individuals, and intrapersonal community variation increased over time at all body sites. Within each season, the frequency of occurrence of most operational taxonomic units (OTUs) was well fitted by a neutral model, highlighting the importance of stochastic forces such as passive dispersal and ecological drift in skin community assembly. Despite the significant richness contributed by neutrally distributed OTUs, skin coassociation networks were dominated by taxa well-adapted to multiple body sites (forehead, forearm, and palm), although hub species were disproportionately rare. Taken together, these results suggest that while skin mycobiome assembly is a predominantly neutral process, taxa that could be under the influence of selective forces (e.g., host selection) are potentially key to the structure of a community network. IMPORTANCE Fungi are well recognized members of the human skin microbiota and are crucial to cutaneous health. Common cutaneous diseases such as seborrheic dermatitis and dermatophytes are linked to fungal species. Most studies related to skin microbial community dynamics have focused on Western subjects, while non-Western individuals are understudied. In this study, we explore the seasonal changes of the skin mycobiome in a healthy Chinese cohort and identify ecological processes that could possibly give rise to such variations. Our work reveals the dynamic nature of host skin fungal community, highlighting the dominant roles neutral forces play in the seasonal assembly of skin mycobiome. This study provides insight into the microbial ecology of the human skin microbiome and fills a knowledge gap in the literature regarding the dynamics of skin fungal community.

Comparison of Healthy and Dandruff Scalp Microbiome Reveals the Role of Commensals in Scalp Health

Several scalp microbiome studies from different populations have revealed the association of dandruff with bacterial and fungal dysbiosis. However, the functional role of scalp microbiota in scalp disorders and health remains scarcely explored. Here, we examined the bacterial and fungal diversity of the scalp microbiome and their potential functional role in the healthy and dandruff scalp of 140 Indian women. Propionibacterium acnes and Staphylococcus epidermidis emerged as the core bacterial species, where the former was associated with a healthy scalp and the latter with dandruff scalp. Along with the commonly occurring Malassezia species (M. restricta and M. globosa) on the scalp, a strikingly high association of dandruff with yet uncharacterized Malassezia species was observed in the core mycobiome. Functional analysis showed that the fungal microbiome was enriched in pathways majorly implicated in cell-host adhesion in the dandruff scalp, while the bacterial microbiome showed a conspicuous enrichment of pathways related to the synthesis and metabolism of amino acids, biotin, and other B-vitamins, which are reported as essential nutrients for hair growth. A systematic measurement of scalp clinical and physiological parameters was also carried out, which showed significant correlations with the microbiome and their associated functional pathways. The results point toward a new potential role of bacterial commensals in maintaining the scalp nutrient homoeostasis and highlights an important and yet unknown role of the scalp microbiome, similar to the gut microbiome. This study, therefore, provides new perspectives on the better understanding of the pathophysiology of dandruff.

A Comparison of Techniques for Collecting Skin Microbiome Samples: Swabbing Versus Tape-Stripping

The swabbing and tape-stripping methods have traditionally been used for collecting skin microbiome samples for skin bacterial analysis, although no reports have compared the outcome of these methods for collecting skin bacteria. Our purpose was to show the differences in microbial composition between samples collected using the swabbing and tape-stripping methods, by both the next generation sequencing and culture studies. The skin microbiome was collected by both methods, and the samples were processed for a sequence-based microbiome analysis and culture study. The next-generation sequencing results showed that skin bacteria collected using the tape-stripping method were comparable to those collected using the swabbing method. In the culture study, the tape-stripping method collected a greater number and wider variety of viable skin bacteria than the swabbing method. These results suggest that the tape-stripping method is comparable to the swabbing method for collecting viable skin bacteria, without losing fidelity to the composition of skin microbiome.

Staphylococcus aureus is the most common bacterial agent of the skin flora of patients with seborrheic dermatitis

Background

Seborrheic dermatitis is an inflammatory skin disease that affects 1–3% of the general population. The Malassezia species has been implicated as the main causative agent; however, the bacterial flora of the skin may also play role in the etiopathogenesis. Therefore, we investigated the most common bacterial agent of the skin flora of patients with seborrheic dermatitis.

Materials and Methods

Fifty-one patients with seborrheic dermatitis and 50 healthy individuals are included in this study. Sterile cotton swabs were rubbed on the scalp of the participants for bacterial culture. Colonial morphology was identified with gram stain and catalase test.

Results

Staphylococcus aureus was isolated from 25 (49%) patients with seborrheic dermatitis and 10 (20%) healthy individuals within the control group. Coagulase-negative staphylococci were isolated from 24 (47.1%) patients with seborrheic dermatitis and 17 (34%) healthy individuals within the control group. Diphtheroids were present in 2 (3.9%) patients and 1 (2%) subject within the control group. Gram-negative bacilli were present only in 1 (2%) patient. Hemolytic streptococci and bacilli were identified in 1 (2%) subject from each group. Colonization of coagulase-negative staphylococci, diphtheroids, gram-negative bacilli, hemolytic streptococci, and bacillus did not differ between patients and healthy controls. However, S. aureus colonization was significantly more common in patients with seborrheic dermatitis than in healthy controls.

Conclusion

Within this study we revealed that S. aureus colonization was significantly higher among the patients. Therefore, we propose that, in addition to the Malassezia species, S. aureus may play a role in the etiopathogenesis of seborrheic dermatitis.

High Staphylococcus epidermidis Colonization and Impaired Permeability Barrier in Facial Seborrheic Dermatitis

BACKGROUND

Seborrheic dermatitis (SD) is a common inflammatory skin condition. The etiology is unclear, although overgrowth of Malassezia on the skin has been suggested to cause SD. This study investigated whether colonization with Staphylococcus plays a role in facial SD, which was not well addressed previously.

METHODS

The study was conducted from September 1, 2011 to February 20, 2012 in the First Hospital of China Medical University. In the first phase, the study evaluated the level of transepidermal water loss (TEWL) and the number of colony-forming units (CFU) of Staphylococcus in defined skin areas of SD patients who were human immunodeficiency virus (HIV) seropositive (HIV [+] SD [+] group, n = 13), classical SD (HIV [-] SD [+] group, n = 24) patients, HIV seropositive-non-SD (HIV [+] SD [-] group, n = 16) patients, and healthy volunteers (HIV [-] SD [-] group, n = 16). In the second phase, we enrolled another cohort of HIV (-) SD (+) patients who applied topical fusidic acid (n = 15), tacrolimus (n = 16), or moisturizer (n = 12). Changes in the Seborrheic Dermatitis Area Severity Index (SDASI), TEWL, and Staphylococcus density were evaluated 2 weeks later. Comparisons of each index were performed using analysis of variance (ANOVA) and least significant difference method.

RESULTS

The level of TEWL was greater through lesional sites in the HIV (+) SD (+) group than that in HIV (+) SD (-) and HIV (-) SD (-) groups (95% confidence interval [CI]: 18.873-47.071, P < 0.001 and 95% CI: 28.755-55.936, P < 0.001, respectively). The number of CFU of Staphylococcus was greater in the HIV (+) SD (+) group than that in HIV (+) SD (-) and HIV (-) SD (-) groups (95% CI: 37.487-142.744, P = 0.001 and 95% CI: 54.936-156.400, P < 0.001, respectively). TEWL was significantly more improved in patients treated with tacrolimus and fusidic acid than that in those treated with moisturizers (95% CI: 7.560-38.987, P = 0.004 and 95% CI: 4.659-37.619, P = 0.011, respectively). Topical tacrolimus and fusidic acid were significantly associated with decreased SDASI as compared with moisturizer (95% CI: 0.03-0.432, P = 0.025 and 95% CI: 0.033-0.44, P = 0.024, respectively).

CONCLUSIONS

High colonization with Staphylococcus epidermidis, along with impaired skin permeability barrier function, contributes to the occurrence of SD.

Mucus glycosylation, immunity and bacterial microbiota associated to the skin of experimentally ulcered gilthead seabream (Sparus aurata)

Interest in fish skin immunity and its associated microbiota has greatly increased among immunologists. The objective of this study is to know if skin ulcers may be associated with changes in the mucus composition and microbial diversity. The abundance of terminal carbohydrates, several enzymes (protease, antiprotease, peroxidase, lysozyme) and total immunoglobulin M levels were evaluated in skin mucus of experimentally ulcered gilthead seabream (Sparus aurata L.). Furthermore, the composition of the microbiota of ulcered and non-ulcered skin has been determined using Illumina Miseq technology. Significant decreases of terminal abundance of α-D-mannose, α-D-glucose and N-acetyl-galactosamine in skin mucus of ulcered fish, compared to control fish were detected. The levels of IgM and all the tested enzymes in mucus were decreased in ulcered fish (compared to control fish) although the observed decreases were only statistically significant for proteases and antiproteases. Concomitantly, the analysis of the composition of the skin microbiota showed clear differences between ulcered and non-ulcered areas. The genus taxonomic analysis showed that Staphylococcus and Lactobacillus were more abundant in non-ulcered skin whereas in ulcered area were Streptococcus and Granulicatella. Important decreases of the number of sequences related to Alteromonas, Thalassabius and Winogradskyella were detected in ulcered skin whilst slight increases of sequences related to Flavobacterium, Chryseobacterium and Tenacibaculum genera were observed. Overall these results demonstrated that the presence of skin ulcers provide microenvironments that perturb both the mucus composition and microbial biodiversity of this important external surface which seem to be more vulnerable to diseases.

The role of microbiota, and probiotics and prebiotics in skin health

During the past decade, scientists have made great strides in understanding the microbiome's role in human health. Today, the microbiome has become key in scientific research, therapeutic development, medical treatment, and as a news feature in the media. Most studies have focused on the microbiome of our gut, but recently researchers have turned their attention to other microbiomes, including that of the skin. These studies of gut and skin microbiomes are yielding very informative results, new treatment strategies, and the development of new prebiotic and probiotic products for the treatment of many skin conditions.

Topical Treatment of Facial Seborrheic Dermatitis: A Systematic Review

BACKGROUND

Facial seborrheic dermatitis (SD), a chronic inflammatory skin condition, can impact quality of life, and relapses can be frequent. Three broad categories of agents are used to treat SD: antifungal agents, keratolytics, and corticosteroids. Topical therapies are the first line of defense in treating this condition.

OBJECTIVE

Our objective was to critically review the published literature on topical treatments for facial SD.

METHODS

We searched PubMed, Scopus, Clinicaltrials.gov, MEDLINE, Embase, and Cochrane library databases for original clinical studies evaluating topical treatments for SD. We then conducted both a critical analysis of the selected studies by grading the evidence and a qualitative comparison of results among and within studies.

RESULTS

A total of 32 studies were eligible for inclusion, encompassing 18 topical treatments for facial SD. Pimecrolimus, the focus of seven of the 32 eligible studies, was the most commonly studied topical treatment.

CONCLUSION

Promiseb^®, desonide, mometasone furoate, and pimecrolimus were found to be effective topical treatments for facial SD, as they had the lowest recurrence rate, highest clearance rate, and the lowest severity scores (e.g., erythema, scaling, and pruritus), respectively. Ciclopirox olamine, ketoconazole, lithium (gluconate and succinate), and tacrolimus are also strongly recommended (level A recommendations) topical treatments for facial SD, as they are consistently effective across high-quality trials (randomized controlled trials).