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Certain aerobic bacteria produce bacterial cellulose (BC) to protect themselves from UV radiation. Inspired by this natural function, the UV-filtering capacity of wet BC film (BC) and dried BC (BC-Dried) is evaluated and it is concluded that both samples hardly filter UVA, but filter UVB to some extent, especially BC-Dried. Moreover, this filtering capacity does not diminish but significantly increases with time, with efficiencies in the 145-160 min time range equal to or greater than most UV filters of the market. This increase in efficiency is due to the fact that the BC structure is modified by prolonged exposure to UVB radiation. Specifically, UVB causes sintering of the cellulose fibers, making the structure denser and increasing its reflection and scattering of UVB radiation. Remarkably, this UVB filtering ability of BC allows it to protect key skin probiotics, Lactobacillus fermentum (L. fermentum) and Cutibacterium acnes (C. acnes), against UVB damage. While the protection of healthy skin microbiota is not currently a regulatory requirement for sunscreens with UV filters, it may become a key differentiator for future UV filters given the increasing evidence on the role of skin microbiota in health.

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Atopic dermatitis (AD) is a common and recurrent skin disease characterized by skin barrier dysfunction, inflammation and chronic pruritus, with wide heterogeneity in terms of age of onset, clinical course and persistence over the lifespan. Although the pathogenesis of the disease are unclear, epidermal barrier dysfunction, immune and microbial dysregulation, and environmental factors are known to be critical etiologies in AD pathology. The skin microbiota represents an ecosystem consisting of numerous microbial species that interact with each other as well as host epithelial cells and immune cells. Although the skin microbiota benefits the host by supporting the basic functions of the skin and preventing the colonization of pathogens, disruption of the microbial balance (dysbiosis) can cause skin diseases such as AD. Although AD is a dermatological disease, recent evidence has shown that changes in microbiota composition in the skin and intestine contribute to the pathogenesis of AD. Environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, diet, irritants, air pollution, epigenetics and microbial exposure. Knowing the microbial combination of intestin, as well as the genetic and epigenetic determinants associated with the development of autoantibodies, may help elucidate the pathophysiology of the disease. The skin of patients with AD is characterized by microbial dysbiosis as a result of reduced microbial diversity and overgrowth of the pathogens such as Staphylococcus aureus. Recent studies have revealed the importance of building a strong immune response against microorganisms during childhood and new mechanisms of microbial community dynamics in modulating the skin microbiome. Numerous microorganisms are reported to modulate host response through communication with keratinocytes, specific immune cells and adipocytes to improve skin health and barrier function. This growing insight into bioactive substances in the skin microbiota has led to novel biotherapeutic approaches targeting the skin surface for the treatment of AD. This review will provide an updated overview of the skin microbiota in AD and its complex interaction with immune response mechanisms, as well as explore possible underlying mechanisms in the pathogenesis of AD and provide insights into new therapeutic developments for the treatment of AD. It also focuses on restoring skin microbial homeostasis, aiming to reduce inflammation by repairing the skin barrier.

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BACKGROUND: The complex ecosystem of the skin microbiome is essential for skin health by acting as a primary defense against infections, regulating immune responses, and maintaining barrier integrity. This literature review aims to consolidate existing information on the skin microbiome, focusing on its composition, functionality, importance, and its impact on skin aging. METHODS: An exhaustive exploration of scholarly literature was performed utilizing electronic databases including PubMed, Google Scholar, and ResearchGate, focusing on studies published between 2011 and 2024. Keywords included "skin microbiome," "skin microbiota," and "aging skin." Studies involving human subjects that focused on the skin microbiome's relationship with skin health were included. Out of 100 initially identified studies, 70 met the inclusion criteria and were reviewed. RESULTS: Studies showed that aging is associated with a reduction in the variety of microorganisms of the skin microbiome, leading to an increased susceptibility to skin conditions. Consequently, this underlines the interest in bacteriotherapy, mainly topical probiotics, to reinforce the skin microbiome in older adults, suggesting improvements in skin health and a reduction in age-related skin conditions. Further exploration is needed into the microbiome's role in skin health and the development of innovative, microbe-based skincare products. Biotherapeutic approaches, including the use of phages, endolysins, probiotics, prebiotics, postbiotics, and microbiome transplantation, can restore balance and enhance skin health. This article also addresses regulatory standards in the EU and the USA that ensure the safety and effectiveness of microbial skincare products. CONCLUSION: This review underscores the need to advance research on the skin microbiome's role in cosmetic enhancements and tailored skincare solutions, highlighting a great interest in leveraging microbial communities for dermatological benefits.

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BACKGROUND: Recent advances have increased the importance of the human microbiome, including the skin microbiome. Despite the hand microbiome research, the factors affecting the composition of the hand microbiome and their personal characteristics are incompletely known. OBJECTIVES: Despite changing environmental factors and personal variation, we aimed to indicate the interpersonal distinction between skin microbiota using simple and rapid molecular methods. METHODS: Over a non-consecutive 10-day period, samples were taken from 10 adult individuals, and ribotyping analysis of the 16S and 23S genes of S. epidermidis was performed on each skin sample. Additionally, EcoRI and HindIII enzyme reactions and variable number tandem repeat (VNTR) reactions of S. epidermidis obtained from DNA samples were performed. The skin microbiomes of individuals were evaluated along with the microbiome profiles left on the surfaces they touched. RESULTS: In the environmental samples taken, it has been observed that people preserve their core skin microbiota characters and carry them to their environment. It was determined that the highest similarity rate was 77.14%, and the lowest similarity rate was 31.74%. CONCLUSION: Our study showed that the core skin microbiota retains its characteristics and leaves traces in environments. The fact that the personal microbiome remains unchanged despite environmental differences and has characteristic features has shown that it can be used in forensic sciences to distinguish individuals from each other. These results with simple and rapid methods further increased the importance and significance of the study. The findings indicate that personal skin microbiota can provide a significant contribution to criminal investigations by increasing accuracy and reliability, especially in forensic analyses.

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Numerous studies have established a strong association between Malassezia and various skin disorders, including atopic dermatitis. Finding appropriate methods or medications to alleviate Malassezia-induced skin damage is of notable public interest. This study aimed to evaluate the therapeutic effect of the exopolysaccharide EPS1, produced by Paenibacillus polymyxa, on Malassezia restricta-induced skin damage. In vitro assays indicated that EPS1 reduced the expression of pro-inflammatory cytokine genes in TNF-α-induced HaCaT cells. In a murine model, EPS1 was found to mitigate clinical symptoms, reduce epidermal thickness and mast cell infiltration, improve skin barrier function, decrease pro-inflammatory cytokine levels associated with type 17 inflammation, enhance Tregs in the spleen, upregulate the transcription of Treg-related genes in skin lesions, and modulate the skin microbiota. This study is the first to report the alleviating effect of Paenibacillus exopolysaccharide on Malassezia-induced skin inflammation and its impact on the skin microbiota. These findings support the potential of Paenibacillus exopolysaccharides as consumer products and therapeutic agents for managing Malassezia-induced skin damage by improving skin barrier function, modulating immune responses, and influencing skin microbiota.

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The human microbiota represents the community and diverse population of microbes within the human body, which comprises approximately 100 trillion micro-organisms. They exist in the human gastrointestinal tract and various other organs and are now considered virtual body organs. It is mainly represented by bacteria but also includes viruses, fungi, and protozoa. Although there is a heritable component to the gut microbiota, environmental factors related to diet, drugs, and anthropometry determine the composition of the microbiota. Besides the gastrointestinal tract, the human body also harbours microbial communities in the skin, oral and nasal cavities, and reproductive tract. The current review demonstrates the role of gut microbiota and its involvement in processing food, drugs, and immune responses. The discussion focuses on the implications of human microbiota in developing several diseases, such as gastrointestinal infections, metabolic disorders, malignancies, etc., through symbiotic relationships. The microbial population may vary depending on the pathophysiological condition of an individual and thus may be exploited as a therapeutic and clinical player. Further, we need a more thorough investigation to establish the correlation between microbes and pathophysiology in humans and propose them as potential therapeutic targets.

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Background: Hepatocellular carcinoma (HCC, or hepatic cancer, HC) and cholangiocarcinoma (CCA, or hepatic bile duct cancer, HBDC) are two major types of primary liver cancer (PLC). Previous studies have suggested that microbiota can either act as risk factors or preventive factors in PLC. However, no study has reported the relationship between skin microbiota and PLC. Therefore, we conducted a two-sample Mendelian randomization (MR) study to assess the causality between skin microbiota and PLC. Methods: Data from the genome-wide association study (GWAS) on skin microbiota were collected. The GWAS summary data of GCST90018803 (HBDC) and GCST90018858 (HC) were utilized in the discovery and verification phases, respectively. The inverse variance weighted (IVW) method was utilized as the principal method in our MR study. The MR-Egger intercept test, Cochran's Q-test, MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and leave-one-out analysis were conducted to identify the heterogeneity and pleiotropy. Results: The results showed that Veillonella (unc.) plays a protective role in HBDC, while the family Neisseriaceae has a positive association with HBDC risk. The class Betaproteobacteria, Veillonella (unc.), and the phylum Bacillota (Firmicutes) play a protective role in HC. Staphylococcus epidermidis, Corynebacterium (unc.), the family Neisseriaceae, and Pasteurellaceae sp. were associated with an increased risk of HC. Conclusion: This study provided new evidence regarding the association between skin microbiota and PLC, suggesting that skin microbiota plays a role in PLC progression. Skin microbiota could be a novel and effective way for PLC diagnosis and treatment.

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Mycosis fungoides (MF) is a cutaneous T-cell lymphoma (CTCL) that is characterized by atypical CD4+ T-cell aggregates in the epidermis. It is typically divided into three clinical phases, which consist of the patches, plaques, and tumor stages. There have been atypical manifestations of MF described in the literature, and it is hypothesized that the skin microbiota plays a role in the skin phenotype of MF patients. Here, we describe an MF patient with multiple, large, ulcerated, and purulent lesions that developed after she swam in the ocean. Our patient was found to have a unique set of bacteria isolated from the wound.

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OBJECTIVE: The purpose of this study is to use two-sample Mendelian randomization (MR) to investigate the causal relationship between skin microbiota, especially Propionibacterium acnes, and intervertebral disc degeneration (IVDD), low back pain (LBP) and sciatica. METHODS: We conducted a two-sample MR using the aggregated data from the whole genome-wide association studies (GWAS). 150 skin microbiota were derived from the GWAS catalog and IVDD, LBP and sciatica were obtained from the IEU Open GWAS project. Inverse-variance weighted (IVW) was the primary research method, with MR-Egger and Weighted median as supplementary methods. Perform sensitivity analysis and reverse MR analysis on all MR results and use multivariate MR to adjust for confounding factors. RESULTS: MR revealed five skin microbiota associated with IVDD, four associated with LBP, and two with sciatica. Specifically, P.acnes in sebaceous skin environments were associated with reduced risk of IVDD; IVDD was found to increase the abundance of P.acnes in moist skin. Furthermore, ASV010 [Staphylococcus (unc.)] from dry skin was a risk factor for LBP and sciatica; ASV045 [Acinetobacter (unc.)] from dry skin and Genus Rothia from dry skin exhibited potential protective effects against LBP; ASV065 [Finegoldia (unc.)] from dry skin was a protective factor for IVDD and LBP. ASV054 [Enhydrobacter (unc.)] from moist skin, Genus Bacteroides from dry skin and Genus Kocuria from dry skin were identified as being associated with an increased risk of IVDD. Genus Streptococcus from moist skin was considered to be associated with an increased risk of sciatica. CONCLUSIONS: This study identified a potential causal relationship between skin microbiota and IVDD, LBP, and sciatica. No evidence suggests skin-derived P.acnes is a risk factor for IVDD, LBP and sciatica. At the same time, IVDD can potentially cause an increase in P.acnes abundance, which supports the contamination theory.

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Background: There is evidence from observational studies that skin microbiota is linked to skin cancers. Nevertheless, the causal association between skin microbiota and skin cancers is yet to be fully clarified. Methods: A bidirectional two-sample Mendelian randomization (MR) was performed to determine the causal relationship between skin microbiota and skin cancers. A total of 294 skin microbial taxa were identified from the first genome-wide association study across three skin microenvironments of two German population cohorts. Summary data of three skin cancers (malignant melanoma, squamous cell carcinoma, and basal cell carcinoma) were obtained from the FinnGen consortium. Moreover, sensitivity analysis examined horizontal pleiotropy and heterogeneity, and microenvironment-based meta-analysis confirmed the reliability of the results. Results: We identified 65 nominal causalities and 5 strong causal associations between skin microbiota and skin cancers. Among them, the class Bacilli revealed a bidirectional positive relationship with malignant melanoma. The class Betaproteobacteria and class Gammaproteobacteria demonstrated a causal association with an elevated risk of malignant melanoma and basal cell carcinoma, respectively. In the reverse MR analysis, malignant melanoma was associated with a lower abundance of phylum Bacteroidetes. There were no indications of significant heterogeneity in instrumental variables or evidence of horizontal pleiotropy. Conclusion: Our MR analysis indicated bidirectional causal associations between skin microbiota and skin cancers, and had the potential to offer novel perspectives on the mechanistic of microbiota-facilitated carcinogenesis.

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As our understanding of dermatological conditions advances, it becomes increasingly evident that traditional pharmaceutical interventions are not universally effective. The intricate balance of the skin microbiota plays a pivotal role in the development of various skin conditions, prompting a growing interest in probiotics, or live biotherapeutic products (LBPs), as potential remedies. Specifically, the topical application of LBPs to modulate bacterial populations on the skin has emerged as a promising approach to alleviate symptoms associated with common skin conditions. This review considers LBPs and their application in addressing a wide spectrum of dermatological conditions with particular emphasis on three key areas: acne, atopic dermatitis, and wound healing. Within this context, the critical role of strain selection is presented as a pivotal factor in effectively managing these dermatological concerns. Additionally, the review considers formulation challenges associated with probiotic viability and proposes a personalised approach to facilitate compatibility with the skin's unique microenvironment. This analysis offers valuable insights into the potential of LBPs in dermatological applications, underlining their promise in reshaping the landscape of dermatological treatments while acknowledging the hurdles that must be overcome to unlock their full potential.

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The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

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Skin microbiomes provide vital functions, yet knowledge about the drivers and processes structuring their species assemblages is limited-especially for non-model organisms. In this study, fish skin microbiome was assessed by high throughput sequencing of amplicon sequence variants from metabarcoding of V3-V4 regions in the 16S rRNA gene on fish hosts subjected to the following experimental manipulations: (i) translocation between fresh and brackish water habitats to investigate the role of environment; (ii) treatment with an antibacterial disinfectant to reboot the microbiome and investigate community assembly and priority effects; and (iii) maintained alone or in pairs to study the role of social environment and inter-host dispersal of microbes. The results revealed that fish skin microbiomes harbour a highly dynamic microbial composition that was distinct from bacterioplankton communities in the ambient water. Microbiome composition first diverged as an effect of translocation to either the brackish or freshwater habitat. When the freshwater individuals were translocated back to brackish water, their microbiome composition converged towards the fish microbiomes in the brackish habitat. In summary, external environmental conditions and individual-specific factors jointly determined the community composition dynamics, whereas inter-host dispersal had negligible effects. The dynamics of the microbiome composition was seemingly non-affected by reboot treatment, pointing towards high resilience to disturbance. The results emphasised the role of inter-individual variability for the unexplained variation found in many host-microbiome systems, although the mechanistic underpinnings remain to be identified.

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Introduction: Atopic dermatitis (AD) is a common clinical recurrent atopic disease in dermatology, most seen in children and adolescents. In recent years, AD has been found to be closely associated with microbial communities. Methods: To explore the synergistic effects between colonizing bacteria from different sites and AD, we comparatively analyzed the skin, oral, and gut microbiota of children with AD (50 individuals) and healthy children (50 individuals) by 16S rRNA gene sequencing. Twenty samples were also randomly selected from both groups for metabolic and macrogenomic sequencing. Results: The results of our sequencing study showed reduced microbiota diversity in the oral, skin, and gut of children with AD (P < 0.05). Metabolomics analysis showed that serotonergic synapse, arachidonic acid metabolism, and steroid biosynthesis were downregulated at all three loci in the oral, skin, and gut of children with AD (P < 0.05). Macrogenomic sequencing analysis showed that KEGG functional pathways of the three site flora were involved in oxidative phosphorylation, ubiquitin-mediated proteolysis, mRNA surveillance pathway, ribosome biogenesis in eukaryotes, proteasome, basal transcription factors, peroxisome, MAPK signaling pathway, mitophagy, fatty acid elongation, and so on (P < 0.05). Discussion: The combined microbial, metabolic, and macrogenetic analyses identified key bacteria, metabolites, and pathogenic pathways that may be associated with AD development. We provides a more comprehensive and in-depth understanding of the role of the microbiota at different sites in AD patients, pointing to new directions for future diagnosis, treatment and prognosis.

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BACKGROUND: Facial aging is a complex process influenced by environmental factors, genetics, and lifestyle. The contribution of the skin microbiota to this process remains poorly understood. METHODS: This two-sample Mendelian randomization (MR) study was performed using genome-wide genotype data from the UK Biobank and previously published studies on skin microbiota. The primary approach for MR analyses included inverse-variance weighting (IVW), MR-Egger regression, simple mode, weighted median, and weighted mode methods. Sensitivity analyses were performed to assess heterogeneity and pleiotropy, and reverse-direction MR analyses were performed to evaluate potential reverse causation. RESULTS: The MR analysis identified ten skin microbiotas with potential causal relationships with facial aging. Protective skin microbiotas included Genus Finegoldia, ASV011 [Staphylococcus (unc.)], ASV008 [Staphylococcus (unc.)], phylum Firmicutes, Family Rhodobacteraceae, and ASV021 [Micrococcus (unc.)], which were negatively associated with facial aging. Conversely, Order Pseudomonadales, Family Moraxellaceae, ASV039 [Acinetobacter (unc.)], and phylum Bacteroidetes were positively associated with facial aging, indicating a risk factor for accelerated aging. Sensitivity analyses confirmed the robustness of these findings, and reverse-direction MR analyses did not suggest any reverse causation. CONCLUSION: This study identified specific skin microbial that may influence facial aging and offered new insights into the rejuvenation strategies. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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Melanin is produced by melanocytes to protect human skin from harmful ultraviolet radiation. During skin cell renewal, melanin and dead skin cells are disposed of. However, prolonged exposure to ultraviolet rays or aging can disturb this cycle, leading to skin hyperpigmentation due to melanin accumulation. Tyrosinase is a crucial enzyme involved in melanin biosynthesis. Although various compounds, including tyrosine inhibitors, that counteract melanin accumulation have been reported, some, such as hydroquinone, are toxic and can cause vitiligo. Meanwhile, the skin is the largest organ and the outermost layer of the immune system, containing a diverse range of bacteria that produce low-toxicity compounds. In the current study, we aim to identify metabolites produced by skin microbiota that inhibit tyrosinase. Specifically, mushroom tyrosinase served as the study model. Following commensal skin bacteria screening, Corynebacterium tuberculostearicum was found to inhibit tyrosinase activity. The active compound was cyclo(l-Pro-l-Tyr); commercially available cyclo(l-Pro-l-Tyr) also exhibited inhibitory activity. Docking simulations suggested that cyclo(l-Pro-l-Tyr) binds to the substrate-binding site of mushroom tyrosinase, obstructing the substrate pocket and preventing its activity. Hence, cyclo(l-Pro-l-Tyr) might have potential applications as a cosmetic agent and food additive.

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BACKGROUND: Observational studies have shown an association between skin microbiota and alopecia areata (AA), but the causal connection remains ambiguous. METHODS: We obtained data on skin microbiota and AA from summary statistics of Genome-Wide Association Studies and applied statistical methods from Mendelian randomization (MR) to assess causal relationships. Additionally, we investigated whether the skin microbiota acts as a mediator in the pathway from gut microbiota to AA. RESULTS: In the MR analysis of KORA FF4 and AA, the inverse-variance weighting method indicated that Corynebacterium (odds ratio [OR] = 0.82, 95% confidence interval [CI]: 0.70-0.96, p = 0.02) and asv037 (OR = 0.87, 95% CI: 0.76-0.99, p = 0.05) exerted protective effects, while Betaproteobacteria (OR = 1.21, 95% CI: 1.01-1.44, p = 0.03), asv015 (OR = 1.27, 95% CI: 1.05-1.54, p = 0.02), and Burkholderiales (OR = 1.20, 95% CI: 1.04-1.38, p = 0.01) were identified as risk factors in AA. In the MR analysis of PopGen and AA, asv001 (OR = 1.12, 95% CI: 1.01-1.24, p = 0.04), asv054 (OR = 1.13, 95% CI: 1.01-1.25, p = 0.03), and asv059 (OR = 1.14, 95% CI: 1.02-1.27, p = 0.02) were found to potentially increase the risk in AA. Furthermore, in the influence of gut microbiota on AA, the skin microbiota did not act as a mediator. CONCLUSION: Our analysis suggests potential causal relationships between certain skin microbiota and AA, revealing insights into its pathogenesis and potential intervention strategies.

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Poly-γ-glutamic acid (γ-PGA) is a carboxylic-acid-rich, bio-derived, water-soluble, edible, hydrating, non-immunogenic polymer produced naturally by several microorganisms. Here, we re-emphasise the ability of Bacillus subtilis natto to naturally produce γ-PGA on whole seaweed, as well as for the yields and chemical properties of the material to be affected by the presence of Mn(2+). Hyaluronic acid (HA) is an extracellular glycosaminoglycan which presents a high concentration of carboxylic acid and hydroxyl groups, being key in fulfilling numerous applications. Currently, there are strong environmental (solvent use), social (non-vegan extraction), and economic factors pushing for the biosynthesis of this material through prokaryotic microorganisms, which is not yet scalable or sustainable. Our study aimed to investigate an innovative raw material which can combine both superior hygroscopicity and UV protection to the cosmetic industry. Comparable hydration effect of commercially available γ-PGA to conventional moisturising agents (HA and glycerol) was observed; however, greater hydration capacity was observed from seaweed-derived γ-PGA. Herewith, successful incorporation of seaweed-derived γ-PGA (0.2-2 w/v%) was achieved for several model cream systems with absorbances reported at 300 and 400 nm. All γ-PGA-based creams displayed shear thinning behaviour as the viscosity decreased, following increasing shear rates. Although the use of commercial γ-PGA within creams did not suggest a significant effect in rheological behaviour, this was confirmed to be a result of the similar molecular weight. Seaweed-derived γ-PGA cream systems did not display any negative effect on model HaCaT keratinocytes by means of in vitro MTT analysis.

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This study aims to explore the impact of the herbal ointment Chushi Zhiyang Ruangao (CSZYRG) on the skin's microecological environment in a mouse model of atopic dermatitis (AD) and to understand the underlying mechanisms involved. The AD model was established in C57 mice using calpolitol (a hypocalcemic analog of vitamin D3; MC903). Medication-free matrix ointment, CSZYRG, and mometasone furoate cream (positive control group) were applied to the injured areas. The skin lesions of AD model mice were photographed. Skin lesions were applied for the hematoxylin and eosin (H&E) staining to observe any pathological changes. Serum immunoglobulin IgE was detected by enzyme-linked immunosorbent assay (ELISA). The changes in the expression of inflammation-related factors TNF-α, IL-1ß, and IL-6 in mice were detected using ELISA and qRT-PCR. Skin microflora samples were taken for 16S rDNA sequencing and analyzed for changes in the skin flora diversity, abundance, and dominant flora in mice. It was concluded that CSZYRG effectively alleviates skin lesions, serum IgE, and levels of TNF-α, IL-1ß, and IL-6 in AD model mice. However, CSZYRG did not affect the skin microbial diversity of AD model mice but could exert an effect on the skin microbial community in AD mice and the relative abundance of the dominant microflora. CSZYRG may play a therapeutic role in AD by affecting the skin microbial community and relative abundance of dominant microflora in AD mice.

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In the wild, C. elegans are emersed in environments teeming with a veritable menagerie of microorganisms. The C. elegans cuticular surface serves as a barrier and first point of contact with their microbial environments. In this study, we identify microbes from C. elegans natural habitats that associate with its cuticle, constituting a simple "skin microbiome." We rear our animals on a modified CeMbio, mCeMbio, a consortium of ecologically relevant microbes. We first combine standard microbiological methods with an adapted micro skin-swabbing tool to describe the skin-resident bacteria on the C. elegans surface. Furthermore, we conduct 16S rRNA gene sequencing studies to identify relative shifts in the proportion of mCeMbio bacteria upon surface-sterilization, implying distinct skin- and gut-microbiomes. We find that some strains of bacteria, including Enterobacter sp. JUb101, are primarily found on the nematode skin, while others like Stenotrophomonas indicatrix JUb19 and Ochrobactrum vermis MYb71 are predominantly found in the animal's gut. Finally, we show that this skin microbiome promotes host cuticle integrity in harsh environments. Together, we identify a skin microbiome for the well-studied nematode model and propose its value in conferring host fitness advantages in naturalized contexts. IMPORTANCE: The genetic model organism C. elegans has recently emerged as a tool for understanding host-microbiome interactions. Nearly all of these studies either focus on pathogenic or gut-resident microbes. Little is known about the existence of native, nonpathogenic skin microbes or their function. We demonstrate that members of a modified C. elegans model microbiome, mCeMbio, can adhere to the animal's cuticle and confer protection from noxious environments. We combine a novel micro-swab tool, the first 16S microbial sequencing data from relatively unperturbed C. elegans, and physiological assays to demonstrate microbially mediated protection of the skin. This work serves as a foundation to explore wild C. elegans skin microbiomes and use C. elegans as a model for skin research.

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