Human Microbiome: Composition and Role in Inflammatory Skin Diseases

Variability in Microbial Communities Driven by Particulate Matter on Human Facial Skin

Microbial communities are known to play an important role in maintaining ecological balance and can be used as an indicator for assessing environmental pollution. Numerous studies have revealed that air pollution can alter the structure of microbial communities, which may increase health risks. Nevertheless, the relationships between microbial communities and particulate matter (PM) caused by air pollution in terms of health risk assessment are not well understood. This study aimed to validate the influences of PM chemical compositions on microbial communities and assess the associated health risks. Our results, based on similarity analysis, revealed that the stability structure of the microbial communities had a similarity greater than 73%. In addition, the altered richness and diversity of microbial communities were significantly associated with PM chemical compositions. Volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) exerted a positive influence on microbial communities in different environmental variables. Additionally, a stronger linear correlation was observed between hydroxyl radicals (·OH) and the richness of microbial communities. All estimated health risks from PM chemical compositions, calculated under different environmental variables, significantly exceeded the acceptable level by a factor of more than 49. Cr and 1,2-Dibromoethane displayed dual adverse effects of non-carcinogenic and carcinogenic risks. Overall, the study provides insights into the fundamental mechanisms of the variability in microbial communities driven by PM, which may support the crucial role of PM chemical compositions in the risk of microorganisms in the atmospheric environment.

New-Onset Hidradenitis Suppurativa in Psoriasis Patients: A Multi-Center, Retrospective Cohort Study

BACKGROUND

Previous research has indicated a potential correlation between hidradenitis suppurativa (HS) and psoriasis (PSO), two chronic inflammatory dermatological diseases. However, there is a lack of comprehensive evaluations that consider a variety of clinical and demographic factors, and the risk of developing HS in PSO patients remains unclear. Our study aims to examine HS risk over time among PSO patients versus matched controls while considering the influence of confounders to provide insights into the potential link between these two diseases.

METHOD

In this multi-institutional cohort study using the TriNetX database, we matched 202,318 patients with PSO with an equivalent number of individuals without PSO, using propensity score matching. The study period extended from 1 January 2005 to 31 December 2018. We computed hazard ratios and their respective 95% confidence intervals (CIs) to evaluate the probability of HS manifestation over a period of 5 years in patients with PSO in comparison to those without PSO.

RESULTS

PSO patients demonstrated a consistently higher risk of developing HS than matched controls across all analytic models with the hazard ratios (HR) ranging from 1.43 (95% CI 1.30-1.56) to 5.91 (95% CI 2.49-14.04). Stratified analyses showed the increased HS risk was observed in both genders but only significant in those aged 18-64 years. Kaplan-Meier analysis indicated PSO patients had a higher cumulative probability of developing HS over time (HR 1.77, 95% CI 1.49-1.89).

CONCLUSIONS

PSO was associated with increased HS risk, highlighting the importance of considering HS as a potential comorbidity in PSO patients and may have implications for early detection, prevention, and management strategies for both conditions. Shared inflammatory pathways, genetic components, and skin dysbiosis may contribute. Further research should elucidate underlying mechanisms.

Exploring the impact of solar radiation on skin microbiome to develop improved photoprotection strategies

The skin microbiome undergoes constant exposure to solar radiation (SR), with its effects on health well-documented. However, understanding SR's influence on host-associated skin commensals remains nascent. This review surveys existing knowledge on SR's impact on the skin microbiome and proposes innovative sun protection methods that safeguard both skin integrity and microbiome balance. A team of skin photodamage specialists conducted a comprehensive review of 122 articles sourced from PubMed and Research Gateway. Key terms included skin microbiome, photoprotection, photodamage, skin cancer, ultraviolet radiation, solar radiation, skin commensals, skin protection, and pre/probiotics. Experts offered insights into novel sun protection products designed not only to shield the skin but also to mitigate SR's effects on the skin microbiome. Existing literature on SR's influence on the skin microbiome is limited. SR exposure can alter microbiome composition, potentially leading to dysbiosis, compromised skin barrier function, and immune system activation. Current sun protection methods generally overlook microbiome considerations. Tailored sun protection products that prioritize both skin and microbiome health may offer enhanced defense against SR-induced skin conditions. By safeguarding both skin and microbiota, these specialized products could mitigate dysbiosis risks associated with SR exposure, bolstering skin defense mechanisms and reducing the likelihood of SR-mediated skin issues.

Very low-calorie ketogenic diet (VLCKD): a therapeutic nutritional tool for acne?

BACKGROUND

Acne, a chronic inflammatory disease impacting the pilosebaceous unit, is influenced significantly by inflammation and oxidative stress, and is commonly associated with obesity. Similarly, obesity is also associated with increased inflammation and oxidation. The role of diet in acne remains inconclusive, but the very low-calorie ketogenic diet (VLCKD), known for weight loss and generating anti-inflammatory ketone bodies, presents promising potential. Despite this, the effects of VLCKD on acne remain underexplored. This study aimed to investigate the efficacy of a 45-day active phase of VLCKD in reducing the clinical severity of acne in young women with treatment-naïve moderate acne and grade I obesity.

METHODS

Thirty-one women with treatment-naïve moderate acne, grade I obesity (BMI 30.03-34.65 kg/m2), aged 18-30 years, meeting inclusion/exclusion criteria, and consenting to adhere to VLCKD were recruited. Baseline and post-intervention assessments included anthropometric measurements, body composition, phase angle (PhA), trimethylamine N-oxide (TMAO) levels, and reactive oxygen metabolite derivatives (dROMs) as markers of inflammation, dysbiosis, and oxidative stress, respectively. A comprehensive dermatological examination, incorporating the Global Acne Grading System (GAGS) and the Dermatology Life Quality Index (DLQI), was conducted for all women.

RESULTS

VLCKD resulted in general improvements in anthropometric and body composition parameters. Significantly, there were significant reductions in both the GAGS score (Δ%: - 31.46 ± 9.53, p < 0.001) and the DLQI score (Δ%: - 45.44 ± 24.02, p < 0.001) after the intervention. These improvements coincided with significant decreases in TMAO (p < 0.001) and dROMs (p < 0.001) levels and a significant increase in PhA (Δ%: + 8.60 ± 7.40, p < 0.001). Changes in the GAGS score positively correlated with changes in dROMs (p < 0.001) and negatively with PhA (p < 0.001) even after adjusting for Δ% FM. Changes in the DLQI score positively correlated with changes in dROMs (p < 0.001) and negatively with PhA (p < 0.001) even after adjustment for Δ% FM.

CONCLUSION

Given the side effects of drugs used for acne, there is an increasing need for safe, tolerable, and low-cost treatments that can be used for acne disease. The 45-day active phase of VLCKD demonstrated notable improvements in acne severity, and these improvements seemed to be attributable to the known antioxidant and anti-inflammatory effects of VLCKD.

Comparative diet-gut microbiome analysis in Crohn's disease and Hidradenitis suppurativa

Introduction

The chronic inflammatory skin disease Hidradenitis suppurativa (HS) is strongly associated with Crohn's Disease (CD). HS and CD share clinical similarities and similar inflammatory pathways are upregulated in both conditions. Increased prevalence of inflammatory disease in industrialised nations has been linked to the Western diet. However, gut microbiota composition and diet interaction have not been compared in HS and CD.

Methods

Here we compared the fecal microbiota (16S rRNA gene amplicon sequencing) and habitual diet of previously reported subjects with HS (n = 55), patients with CD (n = 102) and controls (n = 95).

Results and discussion

Patients with HS consumed a Western diet similar to patients with CD. Meanwhile, habitual diet in HS and CD was significantly different to controls. Previously, we detected differences in microbiota composition among patients with HS from that of controls. We now show that 40% of patients with HS had a microbiota configuration similar to that of CD, characterised by the enrichment of pathogenic genera (Enterococcus, Veillonella and Escherichia_Shigella) and the depletion of putatively beneficial genera (Faecalibacterium). The remaining 60% of patients with HS harboured a normal microbiota similar to that of controls. Antibiotics, which are commonly used to treat HS, were identified as a co-varying with differences in microbiota composition. We examined the levels of several inflammatory markers highlighting that growth-arrest specific 6 (Gas6), which has anti-inflammatory potential, were significantly lower in the 40% of patients with HS who had a CD microbiota configuration. Levels of the pro-inflammatory cytokine IL-12, which is a modulator of intestinal inflammation in CD, were negatively correlated with the abundance of health-associated genera in patients with HS. In conclusion, the fecal microbiota may help identify patients with HS who are at greater risk for development of CD.

Chitosan-coated miconazole as an effective anti-inflammatory agent for the treatment of postoperative infections in obstetrics and vaginal yeast infection control on in vitro evaluations

People with immune deficiency are at risk of developing infections caused by several bacterial and fungal species. In this work, chitosan-coated miconazole was developed by a simple sol-gel method. Miconazole is considered an effective drug to treat vaginal infection-causing bacteria and fungi. The coating of chitosan with miconazole nitrate showed the highest drug loading efficiency (62.43%) and mean particle size (2 μm). FTIR spectroscopic analysis confirmed the entrapment of miconazole nitrate into chitosan polymer. The antifungal result demonstrated that MN@CS microgel possessed notable anti-Aspergillus fumigatus and Candida albicans activity in lower doses. Antibacterial activity results revealed excellent bacterial growth inhibition of MN@CS microgel towards human skin infectious pathogens Escherichia coli and Staphylococcus aureus. The biocompatibility studies of In vitro cell viability and Artemia salina lethality assay suggested that MN@CS microgel is more biosafe and suitable for human external applications. In the future, it will be an efficient anti-inflammatory agent for the treatment of vaginal infections.

The Skin Barrier and Moisturization: Function, Disruption, and Mechanisms of Repair

BACKGROUND

The anatomic layers of the skin are well-defined, and a functional model of the skin barrier has recently been described. Barrier disruption plays a key role in several skin conditions, and moisturization is recommended as an initial treatment in conditions such as atopic dermatitis. This review aimed to analyze the skin barrier in the context of the function model, with a focus on the mechanisms by which moisturizers support each of the functional layers of the skin barrier to promote homeostasis and repair.

SUMMARY

The skin barrier is comprised of four interdependent layers - physical, chemical, microbiologic, and immunologic - which maintain barrier structure and function. Moisturizers target disruption affecting each of these four layers through several mechanisms and were shown to improve transepidermal water loss in several studies. Occlusives, humectants, and emollients occlude the surface of the stratum corneum (SC), draw water from the dermis into the epidermis, and assimilate into the SC, respectively, in order to strengthen the physical skin barrier. Acidic moisturizers bolster the chemical skin barrier by supporting optimal enzymatic function, increasing ceramide production, and facilitating ideal conditions for commensal microorganisms. Regular moisturization may strengthen the immunologic skin barrier by reducing permeability and subsequent allergen penetration and sensitization.

KEY MESSAGES

The physical, chemical, microbiologic, and immunologic layers of the skin barrier are each uniquely impacted in states of skin barrier disruption. Moisturizers target each of the layers of the skin barrier to maintain homeostasis and facilitate repair.

Targeting dysbiosis in psoriasis, atopic dermatitis, and hidradenitis suppurativa: the gut-skin axis and microbiome-directed therapy

Emerging evidence highlights the gut-skin microbiota as a potential therapeutic target for the management of inflammatory-driven cutaneous diseases as well as the interconnection of the gut-skin microbiota in disease pathogenesis and progression. Although not fully understood, recent research has indicated that commensal microbiota and the interaction of the gut-skin axis play an important role in maintaining skin homeostasis. Dysbiosis and disruption of the skin-gut microbiome may lead to impaired skin barrier function, thus triggering downstream inflammatory responses involved in the development of inflammatory skin disorders, especially in atopic dermatitis, psoriasis, and hidradenitis suppurativa. The skin microbiome may also serve as adjunctive therapeutic modalities for treatment. Herein, we review the latest reports on the interrelationship between microbial dysbiosis and inflammatory cutaneous diseases as well as emerging microbiome-directed therapeutics in atopic dermatitis, psoriasis, and hidradenitis suppurativa.

Biodiversity of Skin Microbiota as an Important Biomarker for Wound Healing

Cutaneous wound healing is a natural and complex repair process that is implicated within four stages. However, microorganisms (e.g., bacteria) can easily penetrate through the skin tissue from the wound bed, which may lead to disbalance in the skin microbiota. Although commensal and pathogenic bacteria are in equilibrium in normal skin, their imbalance in the wound area can cause the delay or impairment of cutaneous wounds. Moreover, skin microbiota is in constant crosstalk with the immune system and epithelial cells, which has significance for the healing of a wound. Therefore, understanding the major bacteria species in the cutaneous wound as well as their communication with the immune system has gained prominence in a way that allows for the emergence of a new perspective for wound healing. In this review, the major bacteria isolated from skin wounds, the role of the crosstalk between the cutaneous microbiome and immune system to heal wounds, the identification techniques of these bacteria populations, and the applied therapies to manipulate the skin microbiota are investigated.

Bacterial Metabolites and Inflammatory Skin Diseases

The microbiome and gut-skin axis are popular areas of interest in recent years concerning inflammatory skin diseases. While many bacterial species have been associated with commensalism of both the skin and gastrointestinal tract in certain disease states, less is known about specific bacterial metabolites that regulate host pathways and contribute to inflammation. Some of these metabolites include short chain fatty acids, amine, and tryptophan derivatives, and more that when dysregulated, have deleterious effects on cutaneous disease burden. This review aims to summarize the knowledge of wealth surrounding bacterial metabolites of the skin and gut and their role in immune homeostasis in inflammatory skin diseases such as atopic dermatitis, psoriasis, and hidradenitis suppurativa.

Skin and Gut Microbiome in Hidradenitis Suppurativa: A Systematic Review

Hidradenitis suppurativa (HS) is a chronic skin disease that significantly impairs the quality of life of affected individuals. The disease is characterized by persistent purulent lesions in specific anatomical areas, and its pathophysiology involves multiple factors, including inflammation, genetics, the microbiome, and environmental components. Recent research suggests a potential role for pathogenic bacteria in HS, highlighting the importance of the communication between the human host and the microbiome in maintaining homeostasis and immune system reactivity. However, the exact mechanisms underlying the gut-skin microbial interactions in HS remain unclear. This systematic review aims to examine the existing literature on the differences in skin and gut microbiome composition between HS patients and healthy controls. The review identifies methodological inconsistencies and calls for further research to elucidate the microbiome's role in HS pathogenesis and to explore new therapeutic interventions. The review highlights the need for advancements in microbiome research methodologies, such as metataxonomics and metagenomics, to improve our understanding of the microbiota's impact on health and disease.

Efficacy of an adjuvant Lactobacillus rhamnosus formula in improving skin lesions as assessed by PASI in patients with plaque psoriasis from a university-affiliated, tertiary-referral hospital in São Paulo (Brazil): a parallel, double-blind, randomized clinical trial

Psoriasis is an inflammatory disease of the skin, characterized by erythematous plaques. It is rather common, affecting 2-4% of the population in western countries. Psoriasis' etiology encompasses both genetic and environmental factors. Evidence suggests that the latter reflect the importance of changes in the microbiome for developing the disease. Thus, it is hypothesized that gut microbiome manipulation may arise as a way of treating psoriasis. However, few trials assessed the use of probiotics in psoriasis, although promising results were detected in small studies. Our objective was to assess the efficacy of adjuvant probiotics (Lactobacillus rhamnosus) in treating plaque psoriasis patients. This was a randomized, parallel, placebo-controlled, double-blind trial with two arms: experimental (n = 50) and control (n = 53). Inclusion of subjects and data gathering lasted from November 2020 to August 2021. Subjects were consecutive plaque psoriasis patients under regular follow-up in the Dermatology unit of a university-affiliated, tertiary-referral hospital in São Paulo (Brazil). Eligibility criteria included being over 18 years old, having plaque psoriasis and not having other skin diseases, neoplasms nor systemic inflammatory diseases. Subjects received standard-of-care plus probiotics (Lactobacillus rhamnosus formula). Controls received standard-of-care plus placebo. Primary outcome was skin lesion improvement as assessed by psoriasis area of severity index (PASI) at six months. Secondary outcome was quality-of-life as assessed by dermatology life quality index (DLQI) at six months. Regarding within-group analyses, changes in both PASI and DLQI were non-significant for the experimental group (mean PASI decreased by 1.58, p = 0.105, and mean DLQI increased by 0.05, p = 0.873) and significant for controls (mean PASI decreased by 1.90, p = 0.019, and mean DLQI decreased by 3.33, p = 0.031). Between-group analyses returned non-significant results (p = 0.620). Our findings do not support the hypothesis that gut microbiome modulation via ingestion of Lactobacillus rhamnosus produces clinical improvement in psoriasis patients. Further research is encouraged.Trial registration: Retrospectively registered at the Brazilian Clinical Trials Registry (RBR-8js7t83) on 08/02/2022.

Human skin bacterial microbiota homeostasis: A delicate balance between health and disease

As the largest organ of the body, the skin acts as a barrier to prevent diseases and harbors a variety of beneficial bacteria. Furthermore, the skin bacterial microbiota plays a vital role in health and disease. Disruption of the barrier or an imbalance between symbionts and pathogens can lead to skin disorders or even systemic diseases. In this review, we first provide an overview of research on skin bacterial microbiota and human health, including the composition of skin bacteria in a healthy state, as well as skin bacterial microbiota educating the immune system and preventing the invasion of pathogens. We then discuss the diseases that result from skin microbial dysbiosis, including atopic dermatitis, common acne, chronic wounds, psoriasis, viral transmission, cutaneous lupus, cutaneous lymphoma, and hidradenitis suppurativa. Finally, we highlight the progress that utilizes skin microorganisms for disease therapeutics, such as bacteriotherapy and skin microbiome transplantation. A deeper knowledge of the interaction between human health and disease and the homeostasis of the skin bacterial microbiota will lead to new insights and strategies for exploiting skin bacteria as a novel therapeutic target.

Methotrexate suppresses psoriatic skin inflammation by inhibiting muropeptide transporter SLC46A2 activity

Cytosolic innate immune sensing is critical for protecting barrier tissues. NOD1 and NOD2 are cytosolic sensors of small peptidoglycan fragments (muropeptides) derived from the bacterial cell wall. These muropeptides enter cells, especially epithelial cells, through unclear mechanisms. We previously implicated SLC46 transporters in muropeptide transport in Drosophila immunity. Here, we focused on Slc46a2, which was highly expressed in mammalian epidermal keratinocytes, and showed that it was critical for the delivery of diaminopimelic acid (DAP)-muropeptides and activation of NOD1 in keratinocytes, whereas the related transporter Slc46a3 was critical for delivering the NOD2 ligand MDP to keratinocytes. In a mouse model, Slc46a2 and Nod1 deficiency strongly suppressed psoriatic inflammation, whereas methotrexate, a commonly used psoriasis therapeutic, inhibited Slc46a2-dependent transport of DAP-muropeptides. Collectively, these studies define SLC46A2 as a transporter of NOD1-activating muropeptides, with critical roles in the skin barrier, and identify this transporter as an important target for anti-inflammatory intervention.

The effect of the ketogenic diet on Acne: Could it be a therapeutic tool?

Acne is a chronic inflammatory disease of the pilosebaceous unit resulting from androgen-induced increased sebum production, altered keratinization, inflammation, and bacterial colonization of the hair follicles of the face, neck, chest and back by Propionibacterium acnes. Overall, inflammation and immune responses are strongly implicated in the pathogenesis of acne. Although early colonization with Propionibacterium acnes and family history may play an important role in the disease, it remains unclear exactly what triggers acne and how treatment affects disease progression. The influence of diet on acne disease is a growing research topic, yet few studies have examined the effects of diet on the development and clinical severity of acne disease, and the results have often been contradictory. Interestingly, very low-calorie ketogenic diet (VLCKD) has been associated with both significant reductions in body weight and inflammatory status through the production of ketone bodies and thus it has been expected to reduce the exacerbation of clinical manifestations or even block the trigger of acne disease. Given the paucity of studies regarding the implementation of VLCKD in the management of acne, this review aims to provide evidence from the available scientific literature to support the speculative use of VLCKD in the treatment of acne.

Apigenin: A Therapeutic Agent for Treatment of Skin Inflammatory Diseases and Cancer

The skin is the main barrier between the body and the environment, protecting it from external oxidative stress induced by ultraviolet rays. It also prevents the entrance of infectious agents such as viruses, external antigens, allergens, and bacteria into our bodies. An overreaction to these agents causes severe skin diseases, including atopic dermatitis, pruritus, psoriasis, skin cancer, and vitiligo. Members of the flavonoid family include apigenin, quercetin, luteolin, and kaempferol. Of these, apigenin has been used as a dietary supplement due to its various biological activities and has been shown to reduce skin inflammation by downregulating various inflammatory markers and molecular targets. In this review, we deal with current knowledge about inflammatory reactions in the skin and the molecular mechanisms by which apigenin reduces skin inflammation.

Optimization of DNA extraction and sampling methods for successful forensic microbiome analyses of the skin and saliva

Microbiome studies have contributed to many fields, such as healthcare and medicine; however, these studies are relatively limited in forensics. Microbiome analyses can provide information, such as geolocation and ancestry information, when short tandem repeat (STR) profiling fails. In this study, methods for DNA extraction and sampling from the skin and saliva were optimized for the construction of a Korean Forensic Microbiome Database (KFMD). DNA yields were estimated using four DNA extraction kits, including two automated kits (Maxwell® FSC DNA IQ™ Casework Kit and PrepFiler™ Forensic DNA Extraction Kit, updated) and two manual kits (QIAamp DNA Mini Kit and QIAamp DNA Micro Kit) commonly used in forensic DNA profiling laboratories. Next-generation sequencing of the 16S rRNA V4 region was performed to analyze microbial communities in samples. The Bacterial Transport Swab with Liquid Media (NobleBio), two cotton swabs (PoongSung and Puritan), and nylon-flocked swabs (NobleBio and COPAN) were tested for DNA recovery. The PrepFiler and Maxwell kits showed the highest yields of 3.884 ng/μL and 23.767 ng/μL from the scalp and saliva, respectively. With respect to DNA recovery, nylon-flocked swabs performed better than cotton swabs. The relative abundances of taxa sorted by DNA extraction kits were similar contributions; however, with significant differences in community composition between scalp and saliva samples. Lawsonella and Veillonella were the most abundant genera in the two sample types. Thus, the Maxwell® FSC DNA IQ™ Casework Kit and nylon-flocked swab (NobleBio) were optimal for DNA extraction and collection in microbiome analyses.

Acne Vulgaris, Atopic Dermatitis and Rosacea: The Role of the Skin Microbiota-A Review

The skin harbors a huge number of different microorganisms such as bacteria, fungi and viruses, and it acts as a protective shield to prevent the invasion of pathogens and to maintain the health of the commensal microbiota. Several studies, in fact, have shown the importance of the skin microbiota for healthy skin. However, this balance can be altered by intrinsic and extrinsic factors, leading to the development of skin disease, such as acne vulgaris (AV), atopic dermatitis (AD) and rosacea(RS). Although these diseases are widespread and affect both adolescents and adults, the scientific correlation between these disorders and the skin microbiota and physiological parameters (TEWL, hydration and lipid composition) is still unclear. This review aims to investigate the current literature regarding the correlation between the skin microbiota and its imbalance underlying microbiological aspects, how the skin microbiota changes over the course of the disease and the current possible treatments. The following reported studies show a general imbalance of the bacterial flora. For this reason, more in-depth studies are necessary to explore the different subspecies and strains involved in all three diseases.

Abnormal prostate microbiota composition is associated with experimental autoimmune prostatitis complicated with depression in rats

Background

Microbiota play essential roles in the pathogenesis of prostatitis and depression. However, the changes in prostate microbiota have not yet been explored in rats with prostatitis/depression. This study aimed to investigate the changes of prostate microbiota in rats with prostatitis/depression.

Methods

Rats with experimental autoimmune prostatitis (EAP) complicated with depression were constructed through injection of rat prostate antigen with immunoadjuvants followed by application of chronic unpredictable mild stress (CUMS). The rats were subjected to inflammatory factor detection and behavioral testing to confirm the establishment of the model. Subsequently, the prostate microbiota was assayed in the rats and compared by 16S rRNA gene sequencing.

Results

A rat model of EAP complicated with depression was established and confirmed by increases in IL-1β, IL-6, and TNF-α as well as the occurrence of depressive‐like behaviors. EAP/CUMS significantly altered the richness, evenness, and composition of prostate microbiota. Forty-six taxonomic biomarkers for prostate microbiota were enriched in rats with EAP/depression and exhibited statistically significant and biologically consistent differences. Metabolomics profiling revealed that EAP/depression was associated with reductive acetyl coenzyme A pathway, L-lysine fermentation to acetate and butanoate, protein N-glycosylation and purine nucleobases degradation I, which is regulated by DCE29, Nocardioes, Helicobacter and Dorea.

Conclusion

Findings from the study demonstrate the existence of abnormal prostate microbiota in EAP complicated with depression and may be helpful in the treatment of comorbid diseases of prostatitis and depression.

Bacterial diversity significantly reduces toward the late stages among filarial lymphedema patients in the Ahanta West District of Ghana: A cross-sectional study

Background

Lymphatic Filariasis (LF), a neglected tropical disease, has been speculated to be complicated by secondary bacteria, yet a systematic documentation of these bacterial populations is lacking. Thus, the primary focus of this study was to profile bacteria diversity in the progression of filarial lymphedema among LF individuals with or without wounds.

Methods

A cross-sectional study design recruited 132 LF individuals presenting with lymphedema with or without wounds from eight communities in the Ahanta West District in the Western Region, Ghana. Swabs from the lymphedematous limbs, ulcers, pus, and cutaneous surfaces were cultured using standard culture-based techniques. The culture isolates were subsequently profiled using Matrix-assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry.

Results

Of the 132 LF participants recruited, 65% (85) had filarial lymphedema with no wounds. In total, 84% (235) of the bacterial isolates were identified. The remaining 16% (46) could not be identified with the method employed. Additionally, 129(55%) of the strains belonged to the phylum Firmicutes, while 61 (26%) and 45 (19%) represented Proteobacteria and Actinobacteria, respectively. Generally, irrespective of the samples type (i.e., wound sample and non-wound samples), there was a sharp increase of bacteria diversity from Stages 1 to 3 and a drastic decrease in these numbers by Stage 4, followed by another surge and a gradual decline in the advanced stages of the disease. The Shannon Diversity Index and Equitability for participants with and without wounds were (3.482, 0.94) and (3.023, 0.75), respectively. Further, Staphylococcus haemolyticus and Escherichia coli showed resistance to tetracycline, chloramphenicol, and penicillin.

Conclusion

The present study reveals a sharp decline in bacterial load at the late stages of filarial lymphedema patients. In addition, we report an emerging antimicrobial resistance trend of S. haemolyticus and E. coli against commonly used antibiotics such as tetracycline, chloramphenicol, and penicillin in communities endemic for LF in the Ahanta West District, Ghana. This could pose a huge challenge to the management of the disease; particularly as current treatments are not quite effective against the infection.

The role of the skin microbiome in atopic dermatitis - correlations and consequences

The physical barrier function of the skin is significantly supported by the (epi-)dermal immune system and the skin's own microbiome. Atopic dermatitis is characterized by an imbalance of all these three factors. The skin microbiome establishes itself immediately after birth and plays an important role in the development and maintenance of immune homeostasis. The clinical picture of atopic dermatitis shows, among other things, changes in the skin microbiome. Particularly during an acute phase, a strongly reduced bacterial diversity as well as the dominance of a single pathogen, Staphylococcus aureus, is observed. Staphylococcus aureus exacerbates the inflammatory process; furthermore, the bacteria produce proteases and toxins that further weaken the already severely compromised barrier function of the skin of patients with atopic dermatitis. However, knowledge of dermal dysbiosis also yields new treatment options for the therapy of the disease. In particular, the application of active bacteria represents a direct influence on the skin microbiome. Results of initial clinical studies on various approaches demonstrate promising results; this article provides an overview of work in this area.

Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases

The human intestine hosts diverse microbial communities that play a significant role in maintaining gut-skin homeostasis. When the relationship between gut microbiome and the immune system is impaired, subsequent effects can be triggered on the skin, potentially promoting the development of skin diseases. The mechanisms through which the gut microbiome affects skin health are still unclear. Enhancing our understanding on the connection between skin and gut microbiome is needed to find novel ways to treat human skin disorders. In this review, we systematically evaluate current data regarding microbial ecology of healthy skin and gut, diet, pre- and probiotics, and antibiotics, on gut microbiome and their effects on skin health. We discuss potential mechanisms of the gut-skin axis and the link between the gut and skin-associated diseases, such as psoriasis, atopic dermatitis, acne vulgaris, rosacea, alopecia areata, and hidradenitis suppurativa. This review will increase our understanding of the impacts of gut microbiome on skin conditions to aid in finding new medications for skin-associated diseases.

Disorders of the skin microbiome in atopic dermatitis and psoriasis

The notion of skin microbiome encompasses a heterogeneous group of microorganisms that belong to various taxonomic units, such as bacteria, archaea, viruses, and fungi. The impact of these microbial community constituents upon the epidermal barrier condition, and upon the immune system functioning, is being intensely scrutinized. There is a particular interest in studying the role that the microorganisms of genus Staphylococcus spp. play in the course of physiological and pathological processes occurring in the skin. This review examines in detail the interaction of the microorganisms of genus Staphylococcus spp. with the microbial community constituents, as well as with the skin immune system in normal condition and in the condition associated with inflammatory dermatoses. There are also the data given on S. aureus pathogenicity factors, the data on the impact of this microorganism upon the course of atopic dermatitis, and upon the course of psoriasis. The review examines the role that coagulase-negative staphylococci, S. epidermidis in particular, play in maintaining the microbiome homeostasis. The review as well examines the impact of the skin microbiome upon the development and activity of the skin immune system, and upon maintaining the integrity of the epidermal barrier.

The gut microbiota profile in psoriasis: a Brazilian case-control study

The pathogenesis of psoriasis, an immune-mediated chronic inflammatory skin disease, remains unclear. Studies have shown an association between psoriasis and intestinal inflammation; in this context, the influence of the gut microbiota on the immune response of psoriasis has become a focus of recent research. The present research evaluated the composition and diversity of the gut microbiota of 21 participants with psoriasis from a Brazilian referral dermatology service compared to 24 healthy controls. A stool sample was collected from each participant at the time of inclusion in the study, and the samples were analysed by sequencing the 16S rRNA gene. The recruitment of research participants involved matching between groups by sex, age, body mass index, comorbidities and smoking and the exclusion of several criteria that could potentially influence the gut microbiota and the interpretation of the data. There was an increase in the Dialister genus and Prevotella copri species in patients with psoriasis compared to the control group. A reduction in the Ruminococcus, Lachnospira and Blautia genera, as well as in the Akkermansia muciniphila species, was also verified in the psoriasis group compared to the control group. Furthermore, patients with psoriasis exhibited less gut microbiota diversity than controls.

LimpiAD foam and the potential control of the pressure ulcers onset

Pressure ulcers development is an undesirable event that often worsens the clinical condition of patients already affected by severe pathologies. Since the aetiology of this clinical complication is unclear yet, at current the primary approach to treat the problem is the adoption of suitable patients' assistance procedures. At the same time, the research focuses on finding medicaments or treatment strategies that could prevent the lesions and/or accelerate their healing. The international market's wide range of cosmetic/pharmaceuticals products is mainly topical preparations based on emollient agents to preserve or restore skin homeostasis. On the other hand, the skin microbiome's implication in the pressure ulcers occurrence is mainly unknown. Based on these assumptions, here we tested an innovative preparation, the LimpiAD foam, as a potential preventive strategy of pressure ulcers onset. The active component of this product is composed of hyaluronic acid conjugated with a bacterial cell wall fragment of C. acnes DSM 28251. For LimpiAD foam, we hypothesised a combined action of the two components on the skin tissue, an emollient effect due to the hyaluronic acid properties together with a modulatory effect on the skin microbiota carried out by the component of bacterial derivation. Our results supported the hypothesis and suggested a potential role of LimpiAD foam in pressure ulcers prevention.

A Journey on the Skin Microbiome: Pitfalls and Opportunities

The human skin microbiota is essential for maintaining homeostasis and ensuring barrier functions. Over the years, the characterization of its composition and taxonomic diversity has reached outstanding goals, with more than 10 million bacterial genes collected and cataloged. Nevertheless, the study of the skin microbiota presents specific challenges that need to be addressed in study design. Benchmarking procedures and reproducible and robust analysis workflows for increasing comparability among studies are required. For various reasons and because of specific technical problems, these issues have been investigated in gut microbiota studies, but they have been largely overlooked for skin microbiota. After a short description of the skin microbiota, the review tackles methodological aspects and their pitfalls, covering NGS approaches and high throughput culture-based techniques. Recent insights into the "core" and "transient" types of skin microbiota and how the manipulation of these communities can prevent or combat skin diseases are also covered. Finally, this review includes an overview of the main dermatological diseases, the changes in the microbiota composition associated with them, and the recommended skin sampling procedures. The last section focuses on topical and oral probiotics to improve and maintain skin health, considering their possible applications for skin diseases.

Altered Skin and Gut Microbiome in Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by the formation of nodules, abscesses, and fistula at intertriginous sites. The skin-gut axis is an area of emerging research in inflammatory skin disease and is a potential contributory factor to the pathogenesis of HS. 59 patients with HS provided fecal samples, nasal and skin swabs of affected sites for analysis. 30 healthy controls provided fecal samples and 20 healthy controls provided nasal and skin swabs. We performed bacterial 16S rRNA gene amplicon sequencing on total DNA derived from the samples. Microbiome alpha diversity was significantly lower in the fecal, skin and nasal samples of individuals with HS which may be secondary to disease biology or related to antibiotic usage. Ruminococcus gnavus was more abundant in the fecal microbiome of individuals with HS, which is also reported in Crohn's disease (CD), suggesting comorbidity due to shared gut microbiota alterations. Finegoldia magna was over-abundant in HS skin samples relative to healthy controls. It is possible local inflammation is driven by F. magna through promoting the formation of neutrophil extracellular traps (NET). These alterations in both the gut and skin microbiome in HS warrant further exploration, and therapeutic strategies including fecal microbiota transplant (FMT) or bacteriotherapy could be of benefit.

Antimicrobial peptides and proteins: Interaction with the skin microbiota

The cutaneous microbiota comprises all living skin microorganisms. There is increasing evidence that the microbiota plays a crucial role in skin homeostasis. Accordingly, a dysbiosis of the microbiota may trigger cutaneous inflammation. The need for a balanced microbiota requires specific regulatory mechanisms that control and shape the microbiota. In this review, we highlight the present knowledge suggesting that antimicrobial peptides (AMPs) may exert a substantial influence on the microbiota by controlling their growth. This is supported by own data showing the differential influence of principal skin-derived AMPs on commensal staphylococci. Vice versa, we also illuminate how the cutaneous microbiota interacts with skin-derived AMPs by modulating AMP expression and how microbiota members protect themselves from the antimicrobial activity of AMPs. Taken together, the current picture suggests that a fine-tuned and well-balanced AMP-microbiota interplay on the skin surface may be crucial for skin health.

Tuhuaiyin alleviates imiquimod-induced psoriasis via inhibiting the properties of IL-17-producing cells and remodels the gut microbiota

BACKGROUND

psoriasis is a chronic inflammatory skin disease. The accumulation of IL-17 cytokines in the lesions leads to epidermis proliferation. Traditional Chinese medicine has a significant effect on psoriasis treatment. Among them, Tuhuaiyin is a representative prescription, which has an outstanding curative effect in acute and remission stage.

METHODS

To reveal the target and molecular mechanism of Tuhuaiyin, systematic pharmacology platform and database screening were used to construct the Tuhuaiyin interaction network with compounds, targets and diseases. The intervention of Tuhuaiyin on keratinocyte proliferation and inflammation was verified in the model of psoriasis-like lesions induced by imiquimod. The effect on the number and function of IL-17-producing cells was detected, and the regulatory effect of Tuhuaiyin on gut microbial was explored.

RESULTS

32 selected active molecules in Tuhuaiyin acted on psoriasis biological processes. Tuhuaiyin significantly alleviates erythema and scales in the psoriasis like mouse model induced by imiquimod. Excessive proliferation of keratinocytes and infiltration of inflammatory cells were restrained in the dermis by using Tuhuaiyin. The expression of IL-17 was down-regulated in skin and peripheral blood. The proportion of IL-17-producing cells was decreased in immune organs. And phosphorylation of JNK inhibited in skin lesions. At the same time, the change of gut microbial diversity in the psoriasis-like model was improved.

CONCLUSION

our study predicted and verified the molecular immunological mechanism of Tuhuaiyin, alleviated the abnormal proliferation of keratinocytes by inhibiting the proportion of IL-17-producing cells and the expression of IL-17 cytokines. Taken together, our data identify the therapeutic potential of Tuhuaiyin for psoriasis.

Long-chain saturated fatty acids in breast milk are associated with the pathogenesis of atopic dermatitis via induction of inflammatory ILC3s

Breastfeeding influences the immune system development in infants and may even affect various immunological responses later in life. Breast milk provides a rich source of early nutrition for infant growth and development. However, the presence of certain compounds in breast milk, related to an unhealthy lifestyle or the diet of lactating mothers, may negatively impact infants. Based on a cohort study of atopic dermatitis (AD), we find the presence of damage-associated molecular patterns (DAMPs) activity in the mother's milk. By non-targeted metabolomic analysis, we identify the long-chain saturated fatty acids (LCSFA) as a biomarker DAMPs (+) breast milk samples. Similarly, a mouse model in which breastfed offspring are fed milk high in LCSFA show AD onset later in life. We prove that LCSFA are a type of damage-associated molecular patterns, which initiate a series of inflammatory events in the gut involving type 3 innate lymphoid cells (ILC3s). A remarkable increase in inflammatory ILC3s is observed in the gut, and the migration of these ILC3s to the skin may be potential triggers of AD. Gene expression analysis of ILC3s isolated from the gut reveal upregulation of genes that increase ILC3s and chemokines/chemokine receptors, which may play a role in ILC migration to the skin. Even in the absence of adaptive immunity, Rag1 knockout mice fed a high-LCSFA milk diet develop eczema, accompanied by increased gut ILC3s. We also present that gut microbiota of AD-prone PA milk-fed mice is different from non-AD OA/ND milk-fed mice. Here, we propose that early exposure to LCSFAs in infants may affect the balance of intestinal innate immunity, inducing a highly inflammatory environment with the proliferation of ILC3s and production of interleukin-17 and interleukin-22, these factors may be potential triggers or worsening factors of AD.

Cutaneous Barriers and Skin Immunity

The skin barrier provides us with several lines of protection from outside hazards. Its most outward layers, the stratum corneum and the epidermis seal our body with an acidic, dry, and rather cool surface, hostile to microbes. Yet, there are also fine-tuned interactions between the mostly commensal microbiota on top of the skin surface, with underlying epidermal cells as well as the immune system, to preserve a healthy steady state and to initiate repair processes when necessary. We take a concise look at the recent insights on the inner workings of this complex barrier.

Association of Trimethylamine N-Oxide (TMAO) with the Clinical Severity of Hidradenitis Suppurativa (Acne Inversa)

In this case-control, cross-sectional, observational study, we evaluated circulating trimethylamine n-oxide (TMAO) levels, a gut-derived metabolite associated with inflammation and cardiometabolic risk, in patients with hidradenitis suppurativa (HS), a highly disabling inflammatory skin disease associated with an elevated prevalence of comorbidities, especially cardiovascular and metabolic diseases. In this study, we enrolled 35 naive-treatment patients with HS and 35 controls, matched for sex, age, and body mass index (BMI). HS Sartorius score was 49.0 (33.0–75.0), while according to the Harley system 12 and 23 patients presented grade 1 and grade 2 severity, respectively. HS patients had a lower adherence to the Mediterranean diet (MD) (p = 0.002), lower phase angle (PhA) (p < 0.001), and higher circulating TMAO levels (p < 0.001) than the control group. HS patients with grade 2 rather than grade 1 of Harley grade severity showed a higher BMI (p = 0.007), waist circumference (p = 0.016), total energy intake (p = 0.005), and lower PhA (p < 0.001) and adherence to the MD (p = 0.003). Of interest, patients with Hurley grade 2 of severity exhibited higher circulating TMAO levels (p < 0.001) compared to grade 1. Circulating TMAO levels showed a positive correlation with HS Sartorius score even after adjustment for confounding covariates, including BMI, waist circumference, adherence to the MD, total energy intake, and PhA (r = 0.570, p = 0.001). Using a linear regression model, circulating TMAO levels and PhA were the main predictors of the clinical severity of HS.

Microbiome Signature and Diversity Profiling of Normal Skin of Human in Saudi Arabia

Background: Studying human skin-associated bacterial communities is crucial to understanding human diseases, disease progression, and their role in maintaining human health. Objectives: This study aimed to identify normal (healthy) skin microbiome signatures of eight individuals living in Jeddah, Makkah Al-Mukarramah region, Saudi Arabia. Methods: The study involved the analysis of resident skin microbiome in inner elbow of the right arm after ethical approval is issued and an informed consent form is signed by participant individuals. Results: Phylogenetic tree indicated the existence of four phyla, e.g., Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria. Firmicutes were shown to be the highest in abundance, while Bacteroidetes were the lowest. At the genus level, Staphylococcus was the highest in abundance, while Enterococcus was the lowest. At the species level, Bacillus cereus was the highest in abundance, while Roseomonas mucosa was the lowest. The analysis for the highly abundant operational taxonomic units (OTUs) indicated a dramatic difference between sexes referring to either genera or species of which Staphylococcus sp., Erwinia sp., Pseudomonas sp., Sphingomonas sp., Corynebacterium sp., Propionibacterium acnes, Kocuria palustris are higher in males, while Bacillus cereus, Bacillus sp., Erwinia sp., Corynebacterium sp., Micrococcus sp., Pseudomonas sp. are lower in males. Conclusions: The study succeeded in detecting the skin microbiome of individuals in Saudi Arabia.

Phase angle and Mediterranean diet in patients with acne: Two easy tools for assessing the clinical severity of disease

BACKGROUND

Acne is a chronic, inflammatory and debilitating skin disorder. Dietary factors and nutritional status are among the exacerbating factors of acne. Phase angle (PhA), a direct measure of Bioelectrical Impedance Analysis (BIA), represents an indicator of the chronic inflammatory state. The Mediterranean diet (MD) is a healthy dietary pattern that can exert anti-inflammatory effects in several inflammatory diseases. We aimed to investigate the difference in PhA and adherence to the MD and their associations with the severity of acne in a sample of naïve treatment patients with acne compared to control group.

MATERIALS

In this cross-sectional, case-control, observational study, we enrolled 51 patients with acne and 51 control individuals. Body composition was evaluated by a BIA phase-sensitive system (50 kHz BIA 101 RJL, Akern Bioresearch, Florence, Italy, Akern). For adherence to the MD, we have used the PREvención con DIeta MEDiterránea (PREDIMED) questionnaire. The clinical severity of acne was assessed by using the global acne grading system (GAGS), a quantitative scoring system to assess acne severity.

RESULTS

Patients with acne had a worse body composition, in particular smaller PhA (p = 0.003), and a lower adherence to the MD (p < 0.001) than the control group, in spite of no differences in gender, age and BMI between the two groups. Stratifying patients with acne according to GAGS categories, both PhA (p = 0.006) and PREDIMED score (p = 0.007) decreased significantly in severe acne than mild/moderate acne. The GAGS score was negative correlations with PhA (r = - 0.478, p < 0.001) and PREDIMED score (r = - 0.504, p < 0.001). The results of the multivariate analysis showed PhA and PREDIMED score were the major determinants of GAGS score (p < 0.001). The receiver operator characteristic (ROC) analysis reporting a value of PhA of ≤ 6.1° and a PREDIMED score of ≤ 9 identified patients with acne with the highest clinical severity of the disease.

CONCLUSIONS

Novel correlations were reported between PhA and the degree of adherence to the MD with acne severity. Of interest, PhA and PREDIMED scores might represent possible markers of the severity of acne in a clinical setting. This study highlights how a cooperation between dermatologist and nutritionists might provide a combination key in the complex management of acne patients.

The Microbiome in Hidradenitis Suppurativa: A Review

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic autoinflammatory skin disease. It is characterised by the development of abscesses and nodules in intertriginous anatomical sites. Whilst it is now recognised as an autoinflammatory condition rather than an infective disease, bacteria are implicated in disease pathogenesis.

METHODS

We performed a search of the literature from inception to 12 August 2020 using the search terms "hidradenitis suppurativa", "Verneuil's disease", "acne inversa", "microbiome", "bacteriology" and "microbiology". Studies were included if they assessed the cutaneous, gut or oral bacteria, bacteriology or microbiome in hidradenitis suppurativa.

RESULTS

Twenty-one studies examining the cutaneous microbiome and two studies examining the gastrointestinal microbiome in HS were identified. No studies examining the oral microbiome in HS were identified. A total of 972 patients and 46 healthy controls were included across studies examining the cutaneous microbiome. A total of 100 patients and 36 controls were included across both gut microbiome studies. Coagulase-negative Staphylococcus, anaerobes such as Porphyromonas and Prevotella, and Staphylococcus aureus species were commonly encountered organisms across the included cutaneous microbiome studies. The studies examining the gut microbiome were limited, with one small study demonstrating an alteration in the gut microbiome composition compared to controls. The other study found no alteration to the gut microbiome in patients with HS compared to those with inflammatory bowel disease (IBD) and HS, and IBD and/or psoriasis.

CONCLUSION

Research should be undertaken into the oral microbiome in HS. Further research should be undertaken examining the cutaneous and gut microbiome in HS, and its relationship with documented co-morbidities. Additionally, metagenomics-focused studies may help identify the relationship between microorganisms and host, and this may shed light on new pathways of disease pathogenesis. This may help identify potential future therapeutic targets.

Atopic Dermatitis as a Multifactorial Skin Disorder. Can the Analysis of Pathophysiological Targets Represent the Winning Therapeutic Strategy?

Atopic dermatitis (AD) is a pathological skin condition with complex aetiological mechanisms that are difficult to fully understand. Scientific evidence suggests that of all the causes, the impairment of the skin barrier and cutaneous dysbiosis together with immunological dysfunction can be considered as the two main factors involved in this pathological skin condition. The loss of the skin barrier function is often linked to dysbiosis and immunological dysfunction, with an imbalance in the ratio between the pathogen Staphylococcus aureus and/or other microorganisms residing in the skin. The bibliographic research was conducted on PubMed, using the following keywords: 'atopic dermatitis', 'bacterial therapy', 'drug delivery system' and 'alternative therapy'. The main studies concerning microbial therapy, such as the use of bacteria and/or part thereof with microbiota transplantation, and drug delivery systems to recover skin barrier function have been summarized. The studies examined show great potential in the development of effective therapeutic strategies for AD and AD-like symptoms. Despite this promise, however, future investigative efforts should focus both on the replication of some of these studies on a larger scale, with clinical and demographic characteristics that reflect the general AD population, and on the process of standardisation, in order to produce reliable data.

Enduring neurobehavioral effects induced by microbiota depletion during the adolescent period

The gut microbiota is an essential regulator of many aspects of host physiology. Disruption of gut microbial communities affects gut-brain communication which ultimately can manifest as changes in brain function and behaviour. Transient changes in gut microbial composition can be induced by various intrinsic and extrinsic factors, however, it is possible that enduring shifts in the microbiota composition can be achieved by perturbation at a timepoint when the gut microbiota has not fully matured or is generally unstable, such as during early life or ageing. In this study, we investigated the effects of 3-week microbiota depletion with antibiotic treatment during the adolescent period and in adulthood. Following a washout period to restore the gut microbiota, behavioural and molecular hallmarks of gut-brain communication were investigated. Our data revealed that transient microbiota depletion had long-lasting effects on microbiota composition and increased anxiety-like behaviour in mice exposed to antibiotic treatment during adolescence but not in adulthood. Similarly, gene expression in the amygdala was more severely affected in mice treated during adolescence. Taken together these data highlight the vulnerability of the gut microbiota during the critical adolescent period and the long-lasting impact manipulations of the microbiota can have on gene expression and behaviour in adulthood.

Phenotypic Modulation of Biofilm Formation in a Staphylococcus epidermidis Orthopedic Clinical Isolate Grown Under Different Mechanical Stimuli: Contribution From a Combined Proteomic Study

One of the major causes of prosthetic joint failure is infection. Recently, coagulase negative Staphylococcus epidermidis has been identified as an emergent, nosocomial pathogen involved in subclinical prosthetic joint infections (PJIs). The diagnosis of PJIs mediated by S. epidermidis is usually complex and difficult due to the absence of acute clinical signs derived from the host immune system response. Therefore, analysis of protein patterns in biofilm-producing S. epidermidis allows for the examination of the molecular basis of biofilm formation. Thus, in the present study, the proteome of a clinical isolate S. epidermidis was analyzed when cultured in its planktonic or sessile form to examine protein expression changes depending on culture conditions. After 24 h of culture, sessile bacteria exhibited increased gene expression for ribosomal activity and for production of proteins related to the initial attachment phase, involved in the capsular polysaccharide/adhesin, surface associated proteins and peptidoglycan biosynthesis. Likewise, planktonic S. epidermidis was able to aggregate after 24 h, synthesizing the accumulation associate protein and cell-wall molecules through the activation of the YycFG and ArlRS, two component regulatory pathways. Prolonged culture under vigorous agitation generated a stressful growing environment triggering aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. Further studies will be essential to support these findings in order to further delineate the complex mechanisms of biofilm formation of S. epidermidis and they could provide the groundwork for the development of new drugs against biofilm-related infections, as well as the identification of novel biomarkers of subclinical or chronic infections mediated by these emerging, low virulence pathogens.

Development of humanized mouse and rat models with full-thickness human skin and autologous immune cells

The human skin is a significant barrier for protection against pathogen transmission. Rodent models used to investigate human-specific pathogens that target the skin are generated by introducing human skin grafts to immunocompromised rodent strains. Infection-induced immunopathogenesis has been separately studied in humanized rodent models developed with human lymphoid tissue and hematopoietic stem cell transplants. Successful co-engraftment of human skin, autologous lymphoid tissues, and autologous immune cells in a rodent model has not yet been achieved, though it could provide a means of studying the human immune response to infection in the human skin. Here, we introduce the human Skin and Immune System (hSIS)-humanized NOD-scid IL2Rγ^null (NSG) mouse and Sprague–Dawley-Rag2^tm2hera Il2rγ^tm1hera (SRG) rat models, co-engrafted with human full-thickness fetal skin, autologous fetal lymphoid tissues, and autologous fetal liver-derived hematopoietic stem cells. hSIS-humanized rodents demonstrate the development of human full-thickness skin, along with autologous lymphoid tissues, and autologous immune cells. These models also support human skin infection following intradermal inoculation with community-associated methicillin-resistant Staphylococcus aureus. The co-engraftment of these human skin and immune system components into a single humanized rodent model could provide a platform for studying human skin infections.

Extrinsic Factors Shaping the Skin Microbiome

Human skin, our most environmentally exposed organ, is colonized by a vast array of microorganisms constituting its microbiome. These bacterial communities are crucial for the fulfillment of human physiological functions such as immune system modulation and epidermal development and differentiation. The structure of the human skin microbiome is established during the early life stages, starting even before birth, and continues to be modulated throughout the entire life cycle, by multiple host-related and environmental factors. This review focuses on extrinsic factors, ranging from cosmetics to the environment and antibacterial agents, as forces that impact the human skin microbiome and well-being. Assessing the impact of these factors on the skin microbiome will help elucidate the forces that shape the microbial populations we coexist with. Furthermore, we will gain additional insight into their tendency to stimulate a healthy environment or to increase the propensity for skin disorder development.

16S rDNA based skin microbiome data of healthy individuals and leprosy patients from India

Leprosy is an infectious disease that has predilection in skin and peripheral nerves. Skin has its own microbiome, however it is not extensively studied in Indian leprosy patients. Here, by using next-generation 16S rDNA sequencing, we have attempted to assess the skin associated microbial diversity pertaining to affected and unaffected skin of Indian leprosy patients. A total of 90 skin swab samples were collected from 60 individuals (30 healthy controls, 30 patients) residing in Hyderabad and Miraj, two distinct geographical locations in India to assess the homo/heterogeneity of skin microbial signatures. While a large increase in genus Methylobacterium and Pseudomonas was seen in patients from Miraj and Hyderabad respectively, a considerable decrease in genus Staphylococcus in the leprosy patients (as compared to controls) from both geographical locations was also observed. We expect that, these datasets can not-only provide further interesting insights, but will also help to observe dynamics of microbiome in the diseased state and generate hypotheses to test for skin microbiome transplantation studies in leprosy.

Measurement(s)	DNA
Technology Type(s)	DNA sequencing
Factor Type(s)	experimental condition
Sample Characteristic - Organism	Homo sapiens
Sample Characteristic - Environment	microbial community
Sample Characteristic - Location	India

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.9897089