The skin microbiome: potential for novel diagnostic and therapeutic approaches to cutaneous disease

Comparison of the full-length sequence and sub-regions of 16S rRNA gene for skin microbiome profiling

The skin microbiome plays a pivotal role in human health by providing protective and functional benefits. Furthermore, its inherent stability and individual specificity present novel forensic applications. These aspects have sparked considerable research enthusiasm among scholars across various fields. However, the selection of specific 16S rRNA hypervariable regions for skin microbiome studies is not standardized and should be validated through extensive research tailored to different research objectives and targeted bacterial taxa. Notably, third-generation sequencing (TGS) technology leverages the full discriminatory power of the 16S gene and enables more detailed and accurate microbial community analyses. Here, we conducted full-length 16S sequencing of 141 skin microbiota samples from multiple human anatomical sites using the PacBio platform. Based on this data, we generated derived 16S sub-region data through an in silico experiment. Comparisons between the 16S full-length and the derived variable region data revealed that the former can provide superior taxonomic resolution. However, even with full 16S gene sequencing, limitations arise in achieving 100% taxonomic resolution at the species level for skin samples. Additionally, the capability to resolve high-abundance bacteria (TOP30) at the genus level remains generally consistent across different 16S variable regions. Furthermore, the V1-V3 region offers a resolution comparable with that of full-length 16S sequences, in comparison to other hypervariable regions studied. In summary, while acknowledging the benefits of full-length 16S gene analysis, we propose the targeting of specific sub-regions as a practical choice for skin microbial research, especially when balancing the accuracy of taxonomic classification with limited sequencing resources, such as the availability of only short-read sequencing or insufficient DNA.IMPORTANCESkin acts as the primary barrier to human health. Considering the different microenvironments, microbial research should be conducted separately for different skin regions. Third-generation sequencing (TGS) technology can make full use of the discriminatory power of the full-length 16S gene. However, 16S sub-regions are widely used, particularly when faced with limited sequencing resources including the availability of only short-read sequencing and insufficient DNA. Comparing the 16S full-length and the derived variable region data from five different human skin sites, we confirmed the superiority of the V1-V3 region in skin microbiota analysis. We propose the targeting of specific sub-regions as a practical choice for microbial research.

Skin microbiome profiling reveals the crucial role of microbial metabolites in anti-photoaging

BACKGROUND

Skin microbiota is essential for health maintenance. Photoaging is the primary environmental factor that affects skin homeostasis, but whether it influences the skin microbiota remains unclear.

OBJECTIVE

The objective of this study is to investigate the relationship between photoaging and skin microbiome.

METHODS

A cohort of senior bus drivers was considered as a long-term unilateral ultraviolet (UV) irradiated population. 16S rRNA amplicon sequencing was conducted to assess skin microbial composition variations on different sides of their faces. The microbiome characteristics of the photoaged population were further examined by photoaging guinea pig models, and the correlations between microbial metabolites and aging-related cytokines were analyzed by high-throughput sequencing and reverse transcription polymerase chain reaction.

RESULTS

Photoaging decreased the relative abundance of microorganisms including Georgenia and Thermobifida in human skin and downregulated the generation of skin microbe-derived antioxidative metabolites such as ectoin. In animal models, Lactobacillus and Streptobacillus abundance in both the epidermis and dermis dropped after UV irradiation, resulting in low levels of skin antioxidative molecules and leading to elevated expressions of the collagen degradation factors matrix metalloproteinase (MMP)-1 and MMP-2 and inflammatory factors such as interleukin (IL)-1β and IL-6.

CONCLUSIONS

Skin microbial characteristics have an impact in photoaging and the loss of microbe-derived antioxidative metabolites impairs skin cells and accelerates the aging process. Therefore, microbiome-based therapeutics may have potential in delaying skin aging.

Carbon source competition within the wound microenvironment can significantly influence infection progression

It is becoming increasingly apparent that commensal skin bacteria have an important role in wound healing and infection progression. However, the precise mechanisms underpinning many of these probiotic interactions remain to be fully uncovered. In this work, we demonstrate that the common skin commensal Cutibacterium acnes can limit the pathogenicity of the prevalent wound pathogen Pseudomonas aeruginosa in vivo. We show that this impact on pathogenicity is independent of any effect on growth, but occurs through a significant downregulation of the Type Three Secretion System (T3SS), the primary toxin secretion system utilised by P. aeruginosa in eukaryotic infection. We also show a downregulation in glucose acquisition systems, a known regulator of the T3SS, suggesting that glucose availability in a wound can influence infection progression. C. acnes is well known as a glucose fermenting organism, and we demonstrate that topically supplementing a wound with glucose reverses the probiotic effects of C. acnes. This suggests that introducing carbon source competition within the wound microenvironment may be an effective way to prevent or limit wound infection.

Bacteriocins: potentials and prospects in health and agrifood systems

Bacteriocins are highly diverse, abundant, and heterogeneous antimicrobial peptides that are ribosomally synthesized by bacteria and archaea. Since their discovery about a century ago, there has been a growing interest in bacteriocin research and applications. This is mainly due to their high antimicrobial properties, narrow or broad spectrum of activity, specificity, low cytotoxicity, and stability. Though initially used to improve food quality and safety, bacteriocins are now globally exploited for innovative applications in human, animal, and food systems as sustainable alternatives to antibiotics. Bacteriocins have the potential to beneficially modulate microbiota, providing viable microbiome-based solutions for the treatment, management, and non-invasive bio-diagnosis of infectious and non-infectious diseases. The use of bacteriocins holds great promise in the modulation of food microbiomes, antimicrobial food packaging, bio-sanitizers and antibiofilm, pre/post-harvest biocontrol, functional food, growth promotion, and sustainable aquaculture. This can undoubtedly improve food security, safety, and quality globally. This review highlights the current trends in bacteriocin research, especially the increasing research outputs and funding, which we believe may proportionate the soaring global interest in bacteriocins. The use of cutting-edge technologies, such as bioengineering, can further enhance the exploitation of bacteriocins for innovative applications in human, animal, and food systems.

Altered skin microbiome, inflammation, and JAK/STAT signaling in Southeast Asian ichthyosis patients

BACKGROUND

Congenital ichthyosis (CI) is a collective group of rare hereditary skin disorders. Patients present with epidermal scaling, fissuring, chronic inflammation, and increased susceptibility to infections. Recently, there is increased interest in the skin microbiome; therefore, we hypothesized that CI patients likely exhibit an abnormal profile of epidermal microbes because of their various underlying skin barrier defects. Among recruited individuals of Southeast Asian ethnicity, we performed skin meta-genomics (i.e., whole-exome sequencing to capture the entire multi-kingdom profile, including fungi, protists, archaea, bacteria, and viruses), comparing 36 CI patients (representing seven subtypes) with that of 15 CI age-and gender-matched controls who had no family history of CI.

RESULTS

This case-control study revealed 20 novel and 31 recurrent pathogenic variants. Microbiome meta-analysis showed distinct microbial populations, decreases in commensal microbiota, and higher colonization by pathogenic species associated with CI; these were correlated with increased production of inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in peripheral blood mononuclear cells. In the wounds of CI patients, we identified specific changes in microbiota and alterations in inflammatory pathways, which are likely responsible for impaired wound healing.

CONCLUSIONS

Together, this research enhances our understanding of the microbiological, immunological, and molecular properties of CI and should provide critical information for improving therapeutic management of CI patients.

Characterization of distinct microbiota associated with androgenetic alopecia patients treated and untreated with platelet-rich plasma (PRP)

BACKGROUND

Androgenic alopecia (AGA) is the most common type of hair loss in men, and there are many studies on the treatment of hair loss by platelet-rich plasma (PRP). The human scalp contains a huge microbiome, but its role in the process of hair loss remains unclear, and the relationship between PRP and the microbiome needs further study. Therefore, the purpose of this study was to investigate the effect of PRP treatment on scalp microbiota composition.

METHODS

We performed PRP treatment on 14 patients with AGA, observed their clinical efficacy, and collected scalp swab samples before and after treatment. The scalp microflora of AGA patients before and after treatment was characterized by amplifying the V3-V4 region of the 16 s RNA gene and sequencing for bacterial identification.

RESULTS

The results showed that PRP was effective in the treatment of AGA patients, and the hair growth increased significantly. The results of relative abundance analysis of microbiota showed that after treatment, g_Cutibacterium increased and g_Staphylococcus decreased, which played a stable role in scalp microbiota. In addition, g_Lawsonella decreased, indicating that the scalp oil production decreased after treatment.

CONCLUSIONS

The findings suggest that PRP may play a role in treating AGA through scalp microbiome rebalancing.

Decrypting Skin Microbiome in Psoriasis: Current Status

Background

Psoriasis is an autoimmune, chronic, inflammatory skin condition of multifactorial etiology. Recent studies in human skin microbiome research have revealed the dysbiosis in lesional skin of psoriatic patients, as well as have established the association of dysbiosis in the elicitation of inflammatory response of psoriatic skin.

Objective

The present review aimed to recapitulate the insights of psoriasis lesional skin microbiome studies published in the last 2 decades, and to determine the most important bacterial genera that can be deployed as psoriatic skin microbial signature for therapeutic intervention.

Methods

To achieve the stated objectives, full-text analysis of literature selected through systematic search of digital literature databases has been carried out following PRISMA guidelines.

Results

Literature analysis suggests differential abundance of specific bacterial genera in the lesional psoriatic skin (LPS) compared to normal skin (NS) of psoriasis patients and skin from healthy subjects. These bacterial genera collectively can be utilized as potential biomarker for constructing lesional psoriatic skin specific microbial signature, and to explore the role of bacterial species in maintaining the skin homeostasis. The analysis further revealed that multiple bacterial species instead of a single bacterial species is important for understanding the psoriasis etiogenesis. Furthermore, decreased microbiome stability and increased diversity might have role in the exacerbation of lesions on skin of psoriatic patients.

Conclusion

Considering the importance of human skin microbiome dysbiosis in psoriasis, research efforts should be carried out to develop new therapeutic measures in addition to current therapies by exploiting the human and host-skin-associated microbial genomic and metabolomic knowledge.

Skin surface biomarkers are associated with future development of atopic dermatitis in children with family history of allergic disease

BACKGROUND

Atopic dermatitis (AD) is a common childhood chronic inflammatory skin disorder that can significantly impact quality of life and has been linked to the subsequent development of food allergy, asthma, and allergic rhinitis, an association known as the "atopic march."

OBJECTIVE

The aim of this study was to identify biomarkers collected non-invasively from the skin surface in order to predict AD before diagnosis across a broad age range of children.

METHODS

Non-invasive skin surface measures and biomarkers were collected from 160 children (3-48 months of age) of three groups: (A) healthy with no family history of allergic disease, (B) healthy with family history of allergic disease, and (C) diagnosed AD.

RESULTS

Eleven of 101 children in group B reported AD diagnosis in the subsequent 12 months following the measurements. The children who developed AD had increased skin immune markers before disease onset, compared to those who did not develop AD in the same group and to the control group. In those enrolled with AD, lesional skin was characterized by increased concentrations of certain immune markers and transepidermal water loss, and decreased skin surface hydration.

CONCLUSIONS

Defining risk susceptibility before onset of AD through non-invasive methods may help identify children who may benefit from early preventative interventions.

Cutaneous Dysbiosis and Dermatophytosis: The Unexplored Link

The skin, besides being the largest interface between the body and the external environment, also forms an ecological niche which is populated by almost a trillion microorganisms. These, collectively known as the cutaneous microbiome, form a dynamic yet well-controlled system that resists invasion by pathogenic microorganisms, functioning as the so-called 'microbiological barrier', modulating the body's immune response, indirectly playing a crucial role in the pathogenesis of several inflammatory diseases. The composition and complexity of the microbiome are yet to be fully understood. The term 'dysbiosis' originally was coined in 1908 for a change in the gut microbiome. The potential role of 'cutaneous dysbiosis' in human dermatophytic infections, especially in the backdrop of the current epidemic of chronic, recurrent and treatment-resistant dermatophytosis, is understandably a topic of interest. The purpose of this review was to assess all studies using culture-independent methods for analysing the skin microbiome in various dermatophyte infections. The PubMed and Google Scholar databases were searched using the terms 'microbiome', 'dysbiosis', 'dermatophytes', 'dermatophytosis' and 'tinea'. All studies involving the use of standard sequencing methods for the study of the microbiome in various dermatophytoses were included. A total of four studies assessing the local skin microbiome associated with dermatophytic infections were found-one for tinea capitis, one for onychomycosis (in both psoriatic and nonpsoriatic nails) and two studying patients of tinea pedis. The studies determined the microbiological patterns in patients and compared them with healthy individuals using sequencing methods. Significant differences in the species diversity and counts of the various microorganisms between patient and control groups were demonstrated in all. However, cross-sectional design and the absence of pre- and post-treatment data along with a limited sample size were the major limitations in all of them. No data regarding other forms of tinea, most importantly, tinea cruris, corporis, faciei, etc. were found. The existing studies demonstrate a change in the microbiome or dysbiosis associated with cases of dermatophytosis, but are inadequate to determine a causal association. The changes may also be wholly or partly attributed to the effect of the infection. Further longitudinal studies from different regions of the world, also involving other forms of dermatophytosis, are required to provide a clearer insight and a more representative picture.

The Skin Microbiome: Current Techniques, Challenges, and Future Directions

Skin acts as a barrier that promotes the colonization of bacteria, fungi, archaea, and viruses whose membership and function may differ depending on the various specialized niches or micro-environments of the skin. The group of microorganisms inhabiting the skin, also known as the skin microbiome, offers protection against pathogens while actively interacting with the host's immune system. Some members of the skin microbiome can also act as opportunistic pathogens. The skin microbiome is influenced by factors such as skin site, birth mode, genetics, environment, skin products, and skin conditions. The association(s) of the skin microbiome with health and disease has (have) been identified and characterized via culture-dependent and culture-independent methods. Culture-independent methods (such as high-throughput sequencing), in particular, have expanded our understanding of the skin microbiome's role in maintaining health or promoting disease. However, the intrinsic challenges associated with the low microbial biomass and high host content of skin microbiome samples have hindered advancements in the field. In addition, the limitations of current collection and extraction methods and biases derived from sample preparation and analysis have significantly influenced the results and conclusions of many skin microbiome studies. Therefore, the present review discusses the technical challenges associated with the collection and processing of skin microbiome samples, the advantages and disadvantages of current sequencing approaches, and potential future areas of focus for the field.

Skin barrier immunology from early life to adulthood

Our skin has a unique barrier function, which is imperative for the body's protection against external pathogens and environmental insults. Although interacting closely and sharing many similarities with key mucosal barrier sites, such as the gut and the lung, the skin also provides protection for internal tissues and organs and has a distinct lipid and chemical composition. Skin immunity develops over time and is influenced by a multiplicity of different factors, including lifestyle, genetics, and environmental exposures. Alterations in early life skin immune and structural development may have long-term consequences for skin health. In this review, we summarize the current knowledge on cutaneous barrier and immune development from early life to adulthood, with an overview of skin physiology and immune responses. We specifically highlight the influence of the skin microenvironment and other host intrinsic, host extrinsic (e.g. skin microbiome), and environmental factors on early life cutaneous immunity.

[Impact of preservatives in topicals on the cutaneous microbiota]

Preservatives are used to stabilize topical preparations and protect the user from the influence of pathogenic microbes. After the application of a topical preparation, the matrix undergoes a metamorphosis, and by proportional evaporation of the hydrophilic phase the preservative may accumulate on the skin surface. This is believed to lead to antiseptic effects and may influence the diversity of the cutaneous microbiota. The regulation of the cutaneous microbiome and the associated influencing factors is a complex system that results in highly individualized conditions. Therefore, investigations on the influence of defined interventions are methodologically difficult. In the present proof-of-concept study, potential antiseptic effects of preservatives were investigated in a combination of in vitro and in vivo methods using microbiological culture tests. In addition, the investigations served to develop a clinical study design to answer further questions and use of an extended range of methods. The results support the hypothesis of an antiseptic effect of the tested preservatives (methyl-4-hydroxybenzoate and propyl-4-hydroxybenzoate, potassium sorbate and propylene glycol) on prominent reference bacteria, which could also be observed in clinical settings.

The use of urea for skin barrier correction

The review summarizes information about the main causes and pathogenesis of xerosis cutis as one of the conditions indicating a violation of the epidermal barrier. Xerosis cutis is a clinical sign of a decrease in the amount and/or quality of lipids and/or hydrophilic substances in the stratum corneum of the epidermis. The modern approach to the treatment of dermatoses accompanied by violations of the epidermal barrier includes basic moisturizers. Urea not only moisturizes the skin. It is involved in the regulation of barrier function and antimicrobial protection. It is a low-molecular regulator of protein synthesis in keratinocytes, such as filaggrin, loricrin, involucrin and transglutaminase 1, cathelicidin, beta-defensin-2, water and urea carrier proteins into the cell, as well as proteins that promote the synthesis of intercellular matrix lipids. The main dermatotropic pharmacological effects of urea (hydration of the epidermis, strengthening of the barrier function of the skin, keratolytic effect, increased penetration of drugs into the skin) have been used in dermatological practice for many years. External agents with urea are used to treat skin diseases accompanied by dryness and excessive keratinization, to correct the deformation of nail plates of various genesis, to facilitate the local penetration of medicines. The use of topical UrocrEM5, UrocrEM10, Uroderm ointments containing 5%, 10% and 30% urea, respectively, is effective and safe.

A Randomized, Double-Blind, Placebo-Controlled, Multicentric Study to Evaluate the Efficacy and the Tolerability of a Class II Medical Device in the Treatment of Mild and Moderate Acne

INTRODUCTION

Several options are available to treat acne lesions, including topical benzoyl peroxide, topical retinoids, topical antibiotics, oral antibiotics, hormonal therapy, isotretinoin, and procedural therapies, such as light and laser therapies, although these cause side effects. This study aimed to establish the efficacy and tolerability of a class IIa medical device containing lactic acid, azelaic acid/polyglyceryl-3 copolymer, azelamidopropyl dimethyl amine, and bifida ferment lysate for the treatment of mild and moderate acne lesions.

METHODS

A randomized, double-blind, placebo-controlled, multicentric study was carried out in which 60 persons of both genders aged ≥ 16 years affected by mild or moderate acne were enrolled. Each person used the product twice daily for 2 months. The clinical score (classified as absent, mild, moderate, and severe) of lesions such as blackheads, whiteheads, papules and pustules, erythema, desquamation, sebum secretion, and porphyrins production by a wood lamp was evaluated on the basis of a dermatologist's visual assessment at baseline (t0) and after 2 months of treatment (t1), and the results were compared between groups. Digital photographic images were also taken.

RESULTS

Sixty subjects concluded the trial. It was observed that subjects treated with the medical device (group I) showed overall improvement in the analyzed acne lesions compared with placebo (group II) after 2 months of treatment. The efficacy of the treatment was also expressed as partial and total clearance. The medical device produced higher percentages of both partial and total clearance in all analyzed parameters, compared with the placebo group. The study was safe and well tolerated.

CONCLUSIONS

It was observed that the participants showed an overall improvement of the analyzed lesions in comparison with the placebo group, without adverse events during the trial. Hence, the medical device was found to be safe and effective in the treatment of mild or moderate acne.

Regular Late Bedtime Significantly Affects the Skin Physiological Characteristics and Skin Bacterial Microbiome

Background

Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome.

Objective

To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18-38 years living in Shanghai.

Methods

Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing.

Results

The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water-oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration.

Conclusion

Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.

Whole-Genome Sequencing Reveals Age-Specific Changes in the Human Blood Microbiota

Based on several reports that indicate the presence of blood microbiota in patients with diseases, we became interested in identifying the presence of bacteria in the blood of healthy individuals. Using 37 samples from 5 families, we extracted sequences that were not mapped to the human reference genome and mapped them to the bacterial reference genome for characterization. Proteobacteria account for more than 95% of the blood microbiota. The results of clustering by means of principal component analysis showed similar patterns for each age group. We observed that the class Gammaproteobacteria was significantly higher in the elderly group (over 60 years old), whereas the arcsine square root-transformed relative abundance of the classes Alphaproteobacteria, Deltaproteobacteria, and Clostridia was significantly lower (p < 0.05). In addition, the diversity among the groups showed a significant difference (p < 0.05) in the elderly group. This result provides meaningful evidence of a consistent phenomenon that chronic diseases associated with aging are accompanied by metabolic endotoxemia and chronic inflammation.

T cell activation and bacterial infection in skin wounds of recessive dystrophic epidermolysis bullosa patients

Recessive dystrophic epidermolysis bullosa (RDEB) patients develop poorly healing skin wounds that are frequently colonized with microbiota. Because T cells play an important role in clearing such pathogens, we aimed to define the status of adaptive T cell‐mediated immunity in RDEB wounds. Using a non‐invasive approach for sampling of wound‐associated constituents, we evaluated microbial contaminants in cellular fraction and exudates obtained from RDED wounds. Infectivity and intracellular trafficking of inactivated Staphylococcus aureus was accessed in RDEB keratinocytes. S. aureus and microbial antigen‐specific activation of RDEB wound‐derived T cells were investigated by fluorescence‐activated cell sorting‐based immune‐phenotyping and T‐cell functional assays. We found that RDEB wounds and epithelial cells are most frequently infected with Staphylococcus sp. and Pseudomonas sp. and that S. aureus essentially infects more RDEB keratinocytes and RDEB‐derived squamous cell carcinoma cells than keratinocytes from healthy donors. The RDEB wound‐associated T cells contain populations of CD4⁺ and CD8⁺ peripheral memory T cells that respond to soluble microbial antigens by proliferating and secreting interferon gamma (IFNγ). Moreover, CD8⁺ cytotoxic T lymphocytes recognize S. aureus‐infected RDEB keratinocytes and respond by producing interleukin‐2 (IL‐2) and IFNγ and degranulating and cytotoxically killing infected cells. Prolonged exposure of RDEB‐derived T cells to microbial antigens in vitro does not trigger PD‐1‐mediated T‐cell exhaustion but induces differentiation of the CD4^high population into CD4^highCD25⁺FoxP3⁺ regulatory T cells. Our data demonstrated that adaptive T cell‐mediated immunity could clear infected cells from wound sites, but these effects might be inhibited by PD‐1/Treg‐mediated immuno‐suppression in RDEB.

Anti-mycobacterial activity of heat and pH stable high molecular weight protein(s) secreted by a bacterial laboratory contaminant

BACKGROUND

Tuberculosis currently stands as the second leading cause of deaths worldwide due to single  infectious agent after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The current challenges of drug resistance in tuberculosis highlight an urgent need to develop newer anti-mycobacterial compounds. In the present study, we report the serendipitous discovery of a bacterial laboratory contaminant (LC-1) exhibiting a zone of growth inhibition on an agar plate seeded with Mycobacterium tuberculosis.

RESULTS

We utilized microbiological, biochemical and biophysical approaches to characterize LC-1 and anti-mycobacterial compound(s) in its secretome. Based on 16S rRNA sequencing and BIOLOG analysis, LC-1 was identified as Staphylococcus hominis, a human bacterial commensal. Anti-mycobacterial activity was initially found in 30 kDa retentate that was obtained by ultrafiltration of culture filtrate (CF). SDS-PAGE analysis of peak fractions obtained by size exclusion chromatography of 30 kDa retentate confirmed the presence of high molecular weight (≥ 30 kDa) proteins. Peak fraction-1 (F-1) exhibited inhibitory activity against M. bovis BCG, but not against M. smegmatis, E. coli and S. aureus. The active fraction F-1 was inactivated by treatment with Proteinase K and α-chymotrypsin. However, it retained its anti-mycobacterial activity over a wide range of heat and pH treatment. The anti-mycobacterial activity of F-1 was found to be maintained even after a long storage (~12 months) at - 20 °C. Mass spectrometry analysis revealed that the identified peptide masses do not match with any previously known bacteriocins.

CONCLUSIONS

The present study highlights the anti-mycobacterial activity of high molecular weight protein(s) present in culture filtrate of LC-1, which may be tested further to target M. tuberculosis. The heat and pH stability of these proteins add to their characteristics as therapeutic proteins and may contribute to their long shelf life. LC-1 being a human commensal can be tested in future for its potential as a probiotic to treat tuberculosis.

Advances in Microbiome-Derived Solutions and Methodologies Are Founding a New Era in Skin Health and Care

The microbiome, as a community of microorganisms and their structural elements, genomes, metabolites/signal molecules, has been shown to play an important role in human health, with significant beneficial applications for gut health. Skin microbiome has emerged as a new field with high potential to develop disruptive solutions to manage skin health and disease. Despite an incomplete toolbox for skin microbiome analyses, much progress has been made towards functional dissection of microbiomes and host-microbiome interactions. A standardized and robust investigation of the skin microbiome is necessary to provide accurate microbial information and set the base for a successful translation of innovations in the dermo-cosmetic field. This review provides an overview of how the landscape of skin microbiome research has evolved from method development (multi-omics/data-based analytical approaches) to the discovery and development of novel microbiome-derived ingredients. Moreover, it provides a summary of the latest findings on interactions between the microbiomes (gut and skin) and skin health/disease. Solutions derived from these two paths are used to develop novel microbiome-based ingredients or solutions acting on skin homeostasis are proposed. The most promising skin and gut-derived microbiome interventional strategies are presented, along with regulatory, safety, industrial, and technical challenges related to a successful translation of these microbiome-based concepts/technologies in the dermo-cosmetic industry.

Transcriptional Heterogeneity and the Microbiome of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphomas (CTCL) presents with substantial clinical variability and transcriptional heterogeneity. In the recent years, several studies paved the way to elucidate aetiology and pathogenesis of CTCL using sequencing methods. Several T-cell subtypes were suggested as the source of disease thereby explaining clinical and transcriptional heterogeneity of CTCL entities. Several differentially expressed pathways could explain disease progression. However, exogenous triggers in the skin microenvironment also seem to affect CTCL status. Especially Staphylococcus aureus was shown to contribute to disease progression. Only little is known about the complex microbiome patterns involved in CTCL and how microbial shifts might impact this malignancy. Nevertheless, first hints indicate that the microbiome might at least in part explain transcriptional heterogeneity and that microbial approaches could serve in diagnosis and prognosis. Shaping the microbiome could be a treatment option to maintain stable disease. Here, we review current knowledge of transcriptional heterogeneity of and microbial influences on CTCL. We discuss potential benefits of microbial applications and microbial directed therapies to aid patients with CTCL burden.

Mining for encrypted peptide antibiotics in the human proteome

The emergence of drug-resistant bacteria calls for the discovery of new antibiotics. Yet, for decades, traditional discovery strategies have not yielded new classes of antimicrobial. Here, by mining the human proteome via an algorithm that relies on the sequence length, net charge, average hydrophobicity and other physicochemical properties of antimicrobial peptides, we report the identification of 2,603 encrypted peptide antibiotics that are encoded in proteins with biological function unrelated to the immune system. We show that the encrypted peptides kill pathogenic bacteria by targeting their membrane, modulate gut and skin commensals, do not readily select for bacterial resistance, and possess anti-infective activity in skin abscess and thigh infection mouse models. We also show, in vitro and in the two mouse models of infection, that encrypted antibiotic peptides from the same biogeographical area display synergistic antimicrobial activity. Our algorithmic strategy allows for the rapid mining of proteomic data and opens up new routes for the discovery of candidate antibiotics.

The skin redoxome

Redoxome is the network of redox reactions and redox active species (ReAS) that affect the homeostasis of cells and tissues. Due to the intense and constant interaction with external agents, the human skin has a robust redox signalling framework with specific pathways and magnitudes. The establishment of the skin redoxome concept is key to expanding knowledge of skin disorders and establishing better strategies for their prevention and treatment. This review starts with its definition and progress to propose how the master redox regulators are maintained and activated in the different conditions experienced by the skin and how the lack of redox regulation is involved in the accumulation of several oxidation end products that are correlated with various skin disorders.

Pilot Study on the Forehead Skin Microbiome and Short Chain Fatty Acids Depending on the SC Functional Index in Korean Cohorts

Dry skin is one of the indicators of a compromised skin barrier. An intact skin barrier is not only important to reserve the hydration within the epidermal tissue but also to protect our skin from environmental stressors and inhibit pathogen invasion; damage to the skin barrier may lead to inflammatory skin diseases. Some microbial metabolites such as short chain fatty acids may inhibit or destroy harmful bacteria and regulate the host immune system. The impact of the skin microbiome and short chain fatty acids on skin barrier function was studied in two groups of 75 participants each. The cohort was equally divided in dry and moist skin types, based on stratum corneum (SC) functionality index (SCFI), reflecting the ratio of transepidermal water loss (TEWL). A dry group represents a low SCFI and a moist group a high SCFI. Compared with the dry skin group, propionate and Cutibacterium levels (previously known as Propionibacterium acnes) were significantly higher (p < 0.001) in the moist group. Levels of Cutibacterium were negatively correlated with those of Staphylococcus (p < 0.0001) in both dry and moist groups. The moist group also had a significantly higher propionate concentration (p < 0.001). This study showed that the microbial community and short chain fatty acid concentration may be considered as significant determinants of the SCFI of the skin.

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.

Identification of Metagenomics Structure and Function Associated With Temporal Changes in Rat (Rattus norvegicus) Skin Microbiome During Health and Cutaneous Burn

The cutaneous skin microbiome is host to a vast ensemble of resident microbes that provide essential capabilities including protection of skin barrier integrity and modulation of the host immune response. Cutaneous burn-injury promotes alteration of cutaneous and systemic immune response that can affect both commensal and pathogenic microbes. A cross-sectional study of a limited number of burn patients revealed a difference in the bacteriome of burned versus control participants. Temporal changes of the skin microbiome during health and cutaneous burn-injury remains largely unknown. Furthermore, how this microbial shift relates to community function in the collective metagenome remain elusive. Due to cost considerations and reduced healing time, rodents are frequently used in burn research, despite inherent physiological differences between rodents and human skin. Using a rat burn model, a longitudinal study was conducted to characterize the rat skin bacterial residents and associated community functions in states of health (n = 30) (sham-burned) and when compromised by burn-injury (n = 24). To address the knowledge gap, traumatic thermal injury and disruption of cutaneous surface is associated with genus-level changes in the microbiota, reduced bacterial richness, and altered representation of bacterial genes and associated predicted functions across different skin microbial communities. These findings demonstrate that, upon burn-injury, there is a shift in diversity of the skin's organismal assemblages, yielding a core microbiome that is distinct at the genome and functional level. Moreover, deviations from the core community correlate with temporal changes post-injury and community transition from the state of cutaneous health to disease (burn-injury).

Changes in Skin and Nasal Microbiome and Staphylococcal Species Following Treatment of Atopic Dermatitis with Dupilumab

Investigation of changes in the skin microbiome following treatment of atopic dermatitis (AD) with dupilumab may provide valuable insights into the skin microbiome as a therapeutic target. The aim of this study is to assess changes in the AD skin microbiome following treatment of AD with dupilumab (n = 27). E-swabs were collected from nose, lesional, and nonlesional skin before and after 16 weeks of dupilumab therapy, and the microbiome was analyzed by 16S rRNA and tuf gene sequencing. Data for 17 patients with milder disease receiving treatment with non-targeted therapies are also presented. The results show that both groups experienced clinical improvement (p < 0.001) following dupilumab therapy and that Shannon diversity increased and bacterial community structure changed. The relative abundance of the genus Staphylococcus (S.) and S. aureus decreased, while that of S. epidermidis and S. hominis increased. No significant changes were observed for patients receiving non-targeted treatments. The increases in S. epidermidis and S. hominis and the decrease in S. aureus correlated with clinical improvement. Furthermore, changes in S. hominis and S. epidermidis correlated inversely with S. aureus. In conclusion, treatment with dupilumab significantly changed the skin microbiome and decreased S. aureus. Our results suggest a favorable role of commensal staphylococci in AD.

Characterization of the microbiome of the invasive Asian toad in Madagascar across the expansion range and comparison with a native co-occurring species

Biological invasions are on the rise, with each invader carrying a plethora of associated microbes. These microbes play important, yet poorly understood, ecological roles that can include assisting the hosts in colonization and adaptation processes or as possible pathogens. Understanding how these communities differ in an invasion scenario may help to understand the host's resilience and adaptability. The Asian common toad, Duttaphrynus melanostictus is an invasive amphibian, which has recently established in Madagascar and is expected to pose numerous threats to the native ecosystems. We characterized the skin and gut bacterial communities of D. melanostictus in Toamasina (Eastern Madagascar), and compared them to those of a co-occurring native frog species, Ptychadena mascareniensis, at three sites where the toad arrived in different years. Microbial composition did not vary among sites, showing that D. melanostictus keeps a stable community across its expansion but significant differences were observed between these two amphibians. Moreover, D. melanostictus had richer and more diverse communities and also harboured a high percentage of total unique taxa (skin: 80%; gut: 52%). These differences may reflect the combination of multiple host-associated factors including microhabitat selection, skin features and dietary preferences.

[The skin microbiome-useful for diagnosis and therapy?]

BACKGROUND

Our skin is a very important and complex organ of the body. The microorganisms of the skin, the so-called microbiome, represent an important part of the healthy skin barrier and are influenced by various external and internal factors.

AIM

The question to what extent the skin microbiome represents a diagnostic or even therapeutic target in the context of skin diseases is discussed.

MATERIALS AND METHODS

A literature search was performed.

RESULTS

Several diseases are associated with negative alterations of the skin microbiome. In atopic dermatitis, a correlation between severity and increased availability of Staphylococcus aureus is known, with a loss of bacterial diversity on the skin. In the future, S. aureus will not only be used as a diagnostic marker in atopic dermatitis, but also represents a promising target as a predictive marker for therapeutic success. The role of the skin microbiome in psoriasis has not yet been researched in depth. However, there is evidence that dysbiosis of the skin microbiome contributes to the course of psoriasis and that there is a disturbance in immune tolerance in patients. In the case of acne, the involvement of Cutibacterium acnes in the clinical picture is well known; however, recent findings show that it is not sufficient to identify the species, but certain characteristics of C. acnes strains are associated.

CONCLUSION

Microbial biomarkers are currently only established in atopic dermatitis. For other diseases, this might be the case in the future; however combinations of microorganisms, single species and also strains with specific characteristics must be considered.

Atopic dermatitis: Role of the skin barrier, environment, microbiome, and therapeutic agents

Atopic dermatitis (AD) is a chronic, inflammatory skin disorder characterized by eczematous and pruritic skin lesions. In recent decades, the prevalence of AD has increased worldwide, most notably in developing countries. The enormous progress in our understanding of the complex composition and functions of the epidermal barrier allows for a deeper appreciation of the active role that the skin barrier plays in the initiation and maintenance of skin inflammation. The epidermis forms a physical, chemical, immunological, neuro-sensory, and microbial barrier between the internal and external environment. Not only lesional, but also non-lesional areas of AD skin display many morphological, biochemical and functional differences compared with healthy skin. Supporting this notion, genetic defects affecting structural proteins of the skin barrier, including filaggrin, contribute to an increased risk of AD. There is evidence to suggest that natural environmental allergens and man-made pollutants are associated with an increased likelihood of developing AD. A compromised epidermal barrier predisposes the skin to increased permeability of these compounds. Numerous topical and systemic therapies for AD are currently available or in development; while anti-inflammatory therapy is central to the treatment of AD, some existing and novel therapies also appear to exert beneficial effects on skin barrier function. Further research on the skin barrier, particularly addressing epidermal differentiation and inflammation, lipid metabolism, and the role of bacterial communities for skin barrier function, will likely expand our understanding of the complex etiology of AD and lead to identification of novel targets and the development of new therapies.

89% Vichy mineralizing water with hyaluronic acid is a well-tolerated adjunct treatment that helps restore skin barrier function in dry skin-related inflammatory dermatoses and post-procedure skin care: A Canadian study

INTRODUCTION

Minéral 89 (M89), comprised of 89% Vichy mineralizing water and hyaluronic acid, has been formulated to help strengthen and restore skin barrier.

AIM

Assess tolerance and efficacy of M89 in post-esthetic procedures and dry skin-related facial dermatoses.

METHOD

Adults post-esthetic procedure or presenting with inflammatory dermatoses (47 subjects; mean age 40.9 ± 13.2 years; any Fitzpatrick or skin phototype), applied M89 for 4 weeks, once or twice daily, as an adjuvant treatment. Information on clinical signs and subject-reported symptoms, skin characteristics, tolerance, and subject and investigator satisfaction were collected.

RESULTS

Following 4 weeks of M89 use, significant decreases with complete resolution of erythema (27.6%), desquamation (29.8%), irritation (32%), and skin dehydration (35.8%), as compared to baseline signs and symptoms, were observed. Overall grading improvements for erythema (84.8%; p < 0.001), desquamation (91.7%; %; p < 0.003), irritation (91.7%; %; p < 0.015), and skin hydration (46.2%; p < 0.015) were noted. There was no significant improvement in papules and pustules. Evaluation of subjective signs demonstrated significant decreases in skin sensations such as burning (-73%; p < 0.0001), itching (-71%; p < 0.0001), stinging-tingling (-66.7%; p < 0.0001), as well as in skin dryness (-60%; p < 0.0001). M89 texture was rated very pleasant by 90% of patients. Investigators assessed M89 tolerance to be either good or very good (93%), and satisfactory or highly satisfactory impact on patient's skin (91.5%).

CONCLUSION

M89 is a highly tolerable adjuvant treatment that significantly improved clinical signs and symptoms related to a compromised skin barrier in various facial dermatoses and post-aesthetic procedures.

Comparative Analysis of the Microbiome across the Gut-Skin Axis in Atopic Dermatitis

Atopic dermatitis (AD) is a refractory and relapsing skin disease with a complex and multifactorial etiology. Various congenital malformations and environmental factors are thought to be involved in the onset of the disease. The etiology of the disease has been investigated, with respect to clinical skin symptoms and systemic immune response factors. A gut microbiome–mediated connection between emotional disorders such as depression and anxiety, and dermatologic conditions such as acne, based on the comorbidities of these two seemingly unrelated disorders, has long been hypothesized. Many aspects of this gut–brain–skin integration theory have recently been revalidated to identify treatment options for AD with the recent advances in metagenomic analysis involving powerful sequencing techniques and bioinformatics that overcome the need for isolation and cultivation of individual microbial strains from the skin or gut. Comparative analysis of microbial clusters across the gut–skin axis can provide new information regarding AD research. Herein, we provide a historical perspective on the modern investigation and clinical implications of gut–skin connections in AD in terms of the integration between the two microbial clusters.

From Dysbiosis to Healthy Skin: Major Contributions of Cutibacterium acnes to Skin Homeostasis

Cutibacterium acnes is the most abundant bacterium living in human, healthy and sebum-rich skin sites, such as the face and the back. This bacterium is adapted to this specific environment and therefore could have a major role in local skin homeostasis. To assess the role of this bacterium in healthy skin, this review focused on (i) the abundance of C. acnes in the skin microbiome of healthy skin and skin disorders, (ii) its major contributions to human skin health, and (iii) skin commensals used as probiotics to alleviate skin disorders. The loss of C. acnes relative abundance and/or clonal diversity is frequently associated with skin disorders such as acne, atopic dermatitis, rosacea, and psoriasis. C. acnes, and the diversity of its clonal population, contributes actively to the normal biophysiological skin functions through, for example, lipid modulation, niche competition and oxidative stress mitigation. Compared to gut probiotics, limited dermatological studies have investigated skin probiotics with skin commensal strains, highlighting their unexplored potential.

Microbiome and Metabolome Analyses Reveal Novel Interplay Between the Skin Microbiota and Plasma Metabolites in Psoriasis

Psoriasis is a chronic inflammatory skin disease that affects millions of people worldwide. There is still no effective approach for the clinical treatment of psoriasis. This is largely due to the lack of understanding of the pathological mechanism. Here, we comprehensively characterized the skin microbiome and plasma metabolome alterations of psoriasis patients. We observed that some pathogenic bacteria, including Vibrio, were significantly increased in psoriasis patients. The metabolomics results showed alterations in some metabolic pathways, especially pathways for lipid metabolism. In addition, microbiome-specific metabolites, including bile acids and kynurenine, were significantly changed. Correlation analysis revealed the interplay between the skin microbiota and plasma metabolites, especially between Vibrio and several lipids. Our results provide new evidence for the interplay between the skin microbiome and plasma metabolites, which is dramatically disrupted in psoriasis patients. This study also revealed the mechanism underlying the pathogenesis of psoriasis.

Tracing skin aging process: a mini- review of in vitro approaches

Skin is a rather complex, yet useful organ of our body. Besides, skin aging is a complicated process that gains a growing interest as mediates many molecular processes in our body. Thus, an efficient skin model is important to understand skin aging function as well as to develop an effective innovative product for skin aging treatment. In this mini review, we present in vitro methods for assessments of skin aging in an attempt to pinpoint basic molecular mechanisms behind this process achieving both a better understanding of aging function and an effective  evaluation of potential products or ingredients that counteract aging. Specifically, this study presents in vitro assays such as 2D or 3D skin models, to evaluate skin aging-related processes such as skin moisturization, photoaging, wound healing, menopause, and skin microbiome as novel efforts in the designing of efficacy assessments in the development of skincare products.

Characterizing the Microbiome of the Contracted Breast Capsule Using Next Generation Sequencing

BACKGROUND

Recent work suggests that bacterial biofilms play a role in capsular contracture (CC). However, traditional culture techniques provide only a limited understanding of the bacterial communities present within the contracted breast. Next generation sequencing (NGS) represents an evolution of polymerase chain reaction technology that can sequence all DNA present in a given sample.

OBJECTIVES

The aim of this study was to utilize NGS to characterize the bacterial microbiome of the capsule in patients with CC following cosmetic breast augmentation.

METHODS

We evaluated 32 consecutive patients with Baker grade III or IV CC following augmentation mammoplasty. Specimens were obtained from all contracted breasts (n = 53) during capsulectomy. Tissue specimens from contracted capsules as well as intraoperative swabs of the breast capsule and implant surfaces were obtained. Samples were sent to MicroGenDX Laboratories (Lubbock, TX) for NGS.

RESULTS

Specimens collected from 18 of 32 patients (56%) revealed the presence of microbial DNA. The total number of positive samples was 22 of 53 (42%). Sequencing identified a total of 120 unique bacterial species and 6 unique fungal species. Specimens with microbial DNA yielded a mean [standard deviation] of 8.27 [4.8] microbial species per patient. The most frequently isolated species were Escherichia coli (25% of all isolates), Diaphorobacter nitroreducens (12%), Cutibacterium acnes (12%), Staphylococcus epidermidis (11%), fungal species (7%), and Staphylococcus aureus (6%).

CONCLUSIONS

NGS enables characterization of the bacterial ecosystem surrounding breast implants in unprecedented detail. This is a critical step towards understanding the role this microbiome plays in the development of CC.

LEVEL OF EVIDENCE: 4

Does the Application of a Semiocclusive Dressing Alter the Microflora of Healthy Intact Skin on the Foot?

BACKGROUND

The skin on human feet presents unique environments for the proliferation of potentially pathogenic commensals. This study examined microflora changes on healthy intact skin under a semiocclusive dressing on the medial longitudinal arch of the foot to determine changes in growth, distribution, and frequency of microflora under the dressing.

METHODS

Nine human participants wore a low-adherent, absorbent, semiocclusive dressing on the medial longitudinal arch of the left foot for 2 weeks. An identical location on the right foot was swabbed and used as a control. Each foot was swabbed at baseline, week 1, and week 2. The swabs were cultured for 48 hours. Visual identification, Gram staining, DNase test agar, and a latex slide agglutination test were used to identify genera and species.

RESULTS

Microflora growth was categorized as scant (0-10 colony-forming units [CFU]), light (11-50 CFU), moderate (51-100 CFU), or heavy (>100 CFU). Scant and light growth decreased and moderate and heavy growth increased under the dressing compared with the control. Seven different genera of bacteria were identified. Coagulase-negative Staphylococcus spp appeared most frequently, followed by Corynebacterium spp.

CONCLUSIONS

Changes in microflora distribution, frequency, and growth were found under the dressing, supporting historical studies. Microflora changes were identified as an increase in bioburden and reduction in diversity. The application of similar methods, using more sophisticated identification and analysis techniques and a variety of dressings, could lead to a better understanding of bacterial and fungal growth under dressings, informing better dressing selection to assist the healing process of wounds and prevent infection.

The role of the microbiome in diabetes mellitus

The microbiome is greatly significant for immune system development and homeostasis. Dysbiosis in gut microbial composition and function is linked to immune responses and the development of metabolic diseases, including diabetes mellitus (DM). However, skin microbiome changes in diabetic patients and their role in DM are poorly elucidated. In this review, we summarize recent findings about the association between the gut and skin microbiota and DM, highlighting their roles in the proinflammatory status of DM. Moreover, although there is evidence that the connection between the gut and skin causes the same activated innate immune response, additional studies are needed to explore the mechanism. These findings might inform future DM prevention, diagnosis and treatment.

Interactions between immune system and the microbiome of skin, blood and gut in pathogenesis of rosacea

The increasingly wide use of next-generation sequencing technologies has revolutionised our knowledge of microbial environments associated with human skin, gastrointestinal tract and blood. The collective set of microorganisms influences metabolic processes, affects immune responses, and so directly or indirectly modulates disease. Rosacea is a skin condition of abnormal inflammation and vascular dysfunction, and its progression is affected by Demodex mites on the skin surface. When looking into the effects influencing development of rosacea, it is not only the skin microbiome change that needs to be considered. Changes in the intestinal microbiome and their circulating metabolites, as well as changes in the blood microbiome also affect the progression of rosacea. Recent research has confirmed the increased presence of bacterial genera like Acidaminococcus and Megasphera in the intestinal microbiome and Rheinheimera and Sphingobium in the blood microbiome of rosacea patients. In this review we discuss our current knowledge of the interactions between the immune system and the skin, gut and blood microbiome, with particular attention to rosacea diagnostic opportunities.

Prebiotic Colloidal Oat Supports the Growth of Cutaneous Commensal Bacteria Including S. epidermidis and Enhances the Production of Lactic Acid

Background

Multiple skin conditions have been associated with alterations in the diversity and composition of the skin microbiome, including dry skin and atopic dermatitis. In these conditions, a number of commensal skin bacteria have been implicated in supporting a healthy skin barrier, including Staphylococcus epidermidis. Recent clinical studies in patients with mild-to-moderate atopic dermatitis and dry/itchy skin have shown significantly improved skin barrier function and microbial diversity upon treatment with moisturizers containing 1% colloidal oat. We hypothesized that direct use of colloidal oat by skin microbes contributes to these therapeutic benefits.

Methods

Skin bacterial growth was assessed using the BacT/ALERT system. Staphylococcus aureus and S. epidermidis growth rates and metabolism were compared in an in vitro competition assay. The effect of a 1% colloidal oat-containing moisturizer on lactic acid content of the stratum corneum was clinically assessed in subjects with moderate-to-severe dry skin. S. epidermidis gene expression was evaluated by next-generation mRNA sequencing. Short-chain fatty acids were quantified in bacterial culture supernatants.

Results

In vitro, colloidal oat increased the growth rate of S. epidermidis vs S. aureus, as well as the metabolism of S. epidermidis. Colloidal oat also significantly increased lactic acid concentrations in supernatants of both strains and decreased pH, consistent with clinical findings that 6-week use of a 1% colloidal oat-containing lotion significantly increased lactic acid on dry skin. Further analyses suggest that colloidal oat alters the gene expression profile of S. epidermidis.

Conclusion

Colloidal oat directly affects the growth, metabolism, lactic acid production, and gene expression of skin commensal bacteria, as shown via in vitro studies. The increased production of lactic acid reflects clinical observations with colloidal oat-containing skin moisturizers. Our findings suggest a new mechanism for colloidal oat as a skin prebiotic, which may contribute to improvements in skin and microbiome diversity in various skin conditions, including dry/itchy skin and atopic dermatitis.

Real-Time Culture-Independent Microbial Profiling Onboard the International Space Station Using Nanopore Sequencing

For the past two decades, microbial monitoring of the International Space Station (ISS) has relied on culture-dependent methods that require return to Earth for analysis. This has a number of limitations, with the most significant being bias towards the detection of culturable organisms and the inherent delay between sample collection and ground-based analysis. In recent years, portable and easy-to-use molecular-based tools, such as Oxford Nanopore Technologies’ MinION™ sequencer and miniPCR bio’s miniPCR™ thermal cycler, have been validated onboard the ISS. Here, we report on the development, validation, and implementation of a swab-to-sequencer method that provides a culture-independent solution to real-time microbial profiling onboard the ISS. Method development focused on analysis of swabs collected in a low-biomass environment with limited facility resources and stringent controls on allowed processes and reagents. ISS-optimized procedures included enzymatic DNA extraction from a swab tip, bead-based purifications, altered buffers, and the use of miniPCR and the MinION. Validation was conducted through extensive ground-based assessments comparing current standard culture-dependent and newly developed culture-independent methods. Similar microbial distributions were observed between the two methods; however, as expected, the culture-independent data revealed microbial profiles with greater diversity. Protocol optimization and verification was established during NASA Extreme Environment Mission Operations (NEEMO) analog missions 21 and 22, respectively. Unique microbial profiles obtained from analog testing validated the swab-to-sequencer method in an extreme environment. Finally, four independent swab-to-sequencer experiments were conducted onboard the ISS by two crewmembers. Microorganisms identified from ISS swabs were consistent with historical culture-based data, and primarily consisted of commonly observed human-associated microbes. This simplified method has been streamlined for high ease-of-use for a non-trained crew to complete in an extreme environment, thereby enabling environmental and human health diagnostics in real-time as future missions take us beyond low-Earth orbit.

Microbiome modulation as a novel therapeutic approach in chronic kidney disease

PURPOSE OF REVIEW

Gut dysbiosis has been implicated in the pathogenesis of chronic kidney disease (CKD). Interventions aimed at restoring gut microbiota have emerged as a potential therapeutic option in CKD. This review summarizes the current evidence on gut microbiota-targeted strategies in patients with CKD.

RECENT FINDINGS

A growing number of studies have shown that plant-based diets, low-protein diets, prebiotic, probiotic, and synbiotic supplementation, and constipation treatment may lead to favorable alterations in the gut microbiota. Current evidence suggests that the implementation of both plant-based and low-protein diets has potential benefits for the primary prevention of CKD, and for slowing CKD progression, with minimal risk of hyperkalemia and/or cachexia. The use of prebiotics, probiotics, and synbiotics and laxatives may have beneficial effects on uremic toxin generation, but their evidence is limited for the prevention and treatment of CKD. Recent advances in diagnostic technologies (e.g., high-throughput sequencing and nanotechnology) could enhance rapid diagnosis, monitoring, and design of effective therapeutic strategies for mitigating gut dysbiosis in CKD.

SUMMARY

Plant-based and low-protein diets, prebiotic, probiotic, and synbiotic supplementation, and constipation treatment represent novel gut microbiota-targeted strategies in the conservative management of CKD, which could improve clinical outcomes in CKD.

Living Therapeutics: The Next Frontier of Precision Medicine

Modern medicine has long studied the mechanism and impact of pathogenic microbes on human hosts, but has only recently shifted attention toward the complex and vital roles that commensal and probiotic microbes play in both health and dysbiosis. Fueled by an enhanced appreciation of the human-microbe holobiont, the past decade has yielded countless insights and established many new avenues of investigation in this area. In this review, we discuss advances, limitations, and emerging frontiers for microbes as agents of health maintenance, disease prevention, and cure. We highlight the flexibility of microbial therapeutics across disease states, with special consideration for the rational engineering of microbes toward precision medicine outcomes. As the field advances, we anticipate that tools of synthetic biology will be increasingly employed to engineer functional living therapeutics with the potential to address longstanding limitations of traditional drugs.

Bacteriome Structure, Function, and Probiotics in Fish Larviculture: The Good, the Bad, and the Gaps

Aquaculture is the fastest-growing sector in food production worldwide. For decades, research on animal physiology, nutrition, and behavior established the foundations of best practices in land-based fish rearing and disease control. Current DNA sequencing, bioinformatics, and data science technologies now allow deep investigations of host-associated microbiomes in a tractable fashion. Adequate use of these technologies can illuminate microbiome dynamics and aid the engineering of microbiome-based solutions to disease prevention in an unprecedented manner. This review examines molecular studies of bacterial diversity, function, and host immunitymodulation at early stages of fish development, where microbial infections cause important economic losses. We uncover host colonization and virulence factors within a synthetic assemblage of fish pathogens using high-end comparative genomics and address the use of probiotics and paraprobiotics as applicable disease-prevention strategies in fish larval and juvenile rearing. We finally propose guidelines for future microbiome research of presumed relevance to fish larviculture.

The microbiome and its impact on food allergy and atopic dermatitis in children

Food allergy (FA) affects 4-10% of children, especially children with atopic dermatitis (AD). During infancy the gut microbiome may determine both the course of FA and tolerance to food allergens. Analogically, the skin microbiome changes in the course of AD. Most studies have associated FA with a lower abundance and diversity of Lactobacillales and Clostridiales, but greater numbers of Enterobacterales, while AD in children has been associated with lower numbers of Staphylococcus epidermidis and S. hominis but an abundance of S. aureus and Streptococcus species. An understanding of the impact of the microbiome on the clinical course of FA and AD may allow for the development of new models of allergy treatment and prevention.

Microbiome in the setting of burn patients: implications for infections and clinical outcomes

Burn damage can lead to a state of immune dysregulation that facilitates the development of infections in patients. The most deleterious impact of this dysfunction is the loss of the skin’s natural protective barrier. Furthermore, the risk of infection is exacerbated by protracted hospitalization, urinary catheters, endotracheal intubation, inhalation injury, arterial lines and central venous access, among other mainstays of burn care. Currently, infections comprise the leading cause of mortality after major burn injuries, which highlights the improvements observed over the last 50 years in the care provided to burn victims. The need to implement the empirical selection of antibiotic therapy to treat multidrug-resistant bacteria may concomitantly lead to an overall pervasiveness of difficult-to-treat pathogens in burn centres, as well as the propagation of antimicrobial resistance and the ultimate dysregulation of a healthy microbiome. While preliminary studies are examining the variability and evolution of human and mice microbiota, both during the early and late phase burn injury, one must consider that abnormal microbiome conditions could influence the systemic inflammatory response. A better understanding of the changes in the post-burn microbiome might be useful to interpret the provenance and subsequent development of infections, as well as to come up with inferences on the prognosis of burn patients. This review aims to summarise the current findings describing the microbiological changes in different organs and systems of burn patients and how these alterations affect the risks of infections, complications, and, ultimately, healing.

Reflections on biosafety in acupuncture

Background

Acupuncture is an integrative and complementary practice for which biosafety standards are essential.

Objective

To elicit a reflection on biosafety in acupuncture to reduce occupational hazards associated with infection as adverse effect for both provider and patient.

Methods

The present theoretical essay is grounded on references intentionally selected from June through October 2019.

Results

Infection is the adverse effect most frequently reported for acupuncture practice, which involves considerable risk of microorganism inoculation. Provider awareness should be raised to comply with biosafety principles and thus ensure their and patient safety without any negative implications for the effectiveness of treatment.

Conclusion

We recommended providers to adopt universal biosafety practices during acupuncture procedures.

Impact of spatial proximity on territoriality among human skin bacteria

Bacteria display social behavior and establish cooperative or competitive interactions in the niches they occupy. The human skin is a densely populated environment where many bacterial species live. Thus, bacterial inhabitants are expected to find a balance in these interactions, which eventually defines their spatial distribution and the composition of our skin microbiota. Unraveling the physiological basis of the interactions between bacterial species in organized environments requires reductionist analyses using functionally relevant species. Here, we study the interaction between two members of our skin microbiota, Bacillus subtilis and Staphylococcus epidermidis. We show that B. subtilis actively responds to the presence of S. epidermidis in its proximity by two strategies: antimicrobial production and development of a subpopulation with migratory response. The initial response of B. subtilis is production of chlorotetain, which degrades the S. epidermidis at the colony level. Next, a subpopulation of B. subtilis motile cells emerges. Remarkably this subpopulation slides towards the remaining S. epidermidis colony and engulfs it. A slow response back from S. epidermidis cells give origin to resistant cells that prevent both attacks from B. subtilis. We hypothesized that this niche conquering and back-down response from B. subtilis and S. epidermidis, respectively, which resembles other conflicts in nature as the ones observed in animals, may play a role in defining the presence of certain bacterial species in the specific microenvironments that these bacteria occupy on our skin.

Hidradenitis suppurativa is an autoinflammatory keratinization disease: A review of the clinical, histologic, and molecular evidence

The pathogenic model of hidradenitis suppurativa is in the midst of a paradigm shift away from a disorder of primary follicular occlusion to an autoinflammatory keratinization disease. Observational, experimental, and therapeutic evidence supports the concept of hidradenitis suppurativa as a primarily inflammatory disorder, a disorder of autoimmunity, or both, in contrast to the current prevailing paradigm of primary follicular occlusion. The lack of reliable and high-fidelity disease models has limited the available experimental and mechanistic evidence to support or refute one pathogenic model over another. This scholarly review synthesizes the existing clinical, histologic, and molecular data to evaluate the extant evidence supporting the autoinflammatory paradigm and further informing the molecular mechanisms of hidradenitis suppurativa pathogenesis. Follicular hyperkeratosis/occlusion and perifollicular inflammation coexist in histologic specimens, with interleukin 1α demonstrated to stimulate comedogenesis in the infundibulum. pH elevation in occluded body sites alters the microbiome and amplifies existing T-helper cell type 17 immunoresponses. Known metabolic comorbidities and smoking are known to upregulate interleukin 1α in follicular keratinocytes. Identified genetic variants may alter epidermal growth factor receptor signaling, leading to upregulated keratinocyte inflammatory responses. The process of follicular rupture and dermal tunnel formation can be explained as secondary responses to inflammatory activation of fibroblasts and epithelial-mesenchymal transition, with antibody production associated with inflammatory amplification in advanced disease. This review aims to reevaluate and integrate the current clinical, histologic, and molecular data into a pathogenic model of hidradenitis suppurativa. This is essential to advance our understanding of the disease and identify novel therapeutic targets and approaches.