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.

The epidermal lipid barrier in microbiome-skin interaction.

The corneocyte layers forming the upper surface of mammalian skin are embedded in a lamellar-membrane matrix which repels harmful molecules while retaining solutes from subcutaneous tissues. Only certain bacterial and fungal taxa colonize skin surfaces. They have ways to use epidermal lipids as nutrients while resisting antimicrobial fatty acids. Skin microorganisms release lipophilic microbe-associated molecular pattern (MAMP) molecules which are largely retained by the epidermal lipid barrier. Skin barrier defects, as in atopic dermatitis, impair lamellar-membrane integrity, resulting in altered skin microbiomes, which then include the pathogen Staphylococcus aureus. The resulting increased penetration of MAMPs and toxins promotes skin inflammation. Elucidating how microorganisms manipulate the epidermal lipid barrier will be key for better ways of preventing inflammatory skin disorders.

Do Kinesio tapes increase the skin exposure to pathogenic bacteria?

BACKGROUND: Kinesio tapes (KTs) are tapes used in physical therapy and athletics. We sought to evaluate if wearing KTs for extended periods of time increases exposure to antibiotic resistant opportunistic pathogens and/or effects normal human skin bacteria. METHODS: The study consisted of 10 volunteers wearing 9 KTs on their arms for 5 consecutive days. Microorganisms were isolated from fragments collected on the second and fifth day then analyzed. Bacteria were identified using the BIOLOG system. Resistance to selected antibiotics was performed using E-Test. The effect of KTs on the growth of Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus was evaluated in a diffusion-based assay. RESULTS: We found that KTs accumulated environmental bacteria. Among 22 species 8 were opportunistic pathogens, and all of them exhibited resistance to at least one antibiotic. None of the tapes produced inhibition zones against S. aureus. One tape, Leukotape P, caused growth inhibition in non-pathogenic S. epidermidis and M. luteus. The adhesive material of the tapes inhibited the growth of all tested bacteria. CONCLUSIONS: These results indicate that KTs may increase the exposure to antibiotic resistant pathogens which can accumulate from the environment. Further, extended exposure could lead to changes in normal skin microbiota, potentially contributing to increased risks of skin infections.

Evaluation of CRISPR Diversity in the Human Skin Microbiome for Personal Identification.

The highly personalized human skin microbiome may serve as a viable marker in personal identification. Amplicon sequencing resolution using 16S rRNA cannot identify bacterial communities sufficiently to discriminate between individuals. Thus, novel higher-resolution genetic markers are required for forensic purposes. The clustered regularly interspaced short palindromic repeats (CRISPRs) are prokaryotic genetic elements that can provide a history of infections encountered by the bacteria. The sequencing of CRISPR spacers may provide phylogenetic information with higher resolution than other markers. However, using spacer sequencing for discrimination of personal skin microbiome is difficult due to limited information on CRISPRs in human skin microbiomes. It remains unclear whether personal microbiome discrimination can be achieved using spacer diversity or which CRISPRs will be forensically relevant. We identified common CRISPRs in the human skin microbiome via metagenomic reconstruction and used amplicon sequencing for deep sequencing of spacers. We successfully reconstructed 24 putative CRISPR arrays using metagenomic data sets. A total of 1,223,462 reads from three CRISPR arrays revealed that spacers in the skin microbiome were highly personalized, and conserved repeats were commonly shared between individuals. These individual specificities observed using CRISPR typing were confirmed by comparing the CRISPR diversity to microbiome diversity assessed using 16S rRNA amplicon sequencing. CRISPR typing achieved 95.2% accuracy in personal classification, whereas 16S rRNA sequencing only achieved 52.6%. These results suggest that sequencing CRISPRs in the skin microbiome may be a more powerful approach for personal identification and ecological studies compared to conventional 16S rRNA sequencing.IMPORTANCE Microbial community diversity analysis can be utilized to characterize the personal microbiome that varies between individuals. CRISPR sequences, which reflect virome structure, in the human skin environment may be highly personalized similar to the structures of individual viromes. In this study, we identified 24 putative CRISPR arrays using a shotgun metagenome data set of the human skin microbiome. The findings of this study expand our understanding of the nature of CRISPRs by identifying novel CRISPR candidates. We developed a method to efficiently determine the diversity of three CRISPR arrays. Our analysis revealed that the CRISPR spacer diversity in the human skin microbiome is highly personalized compared with the microbiome diversity assessed by 16S rRNA sequencing, providing a new perspective on the study of the skin microbiome.

Improvement of Atopic Dermatitis by Synbiotic Baths.

Atopic dermatitis (AD) is a widespread chronic inflammatory dermatologic disorder. This randomized, double-blind study aims to evaluate the effect of synbiotic baths with a defined mixture of six viable lactic acid bacteria (LAB) and prebiotics, without bacteria and prebiotics and placebo baths without prebiotics and bacteria to treat AD patients over a period of 14 days. Therefore, AD patients were randomly assigned into three groups using synbiotic (n = 7), prebiotics (n = 8) or placebo baths (n = 7). Severity of AD was evaluated over time by using severity scoring of atopic dermatitis (SCORAD) and by patient questionnaires. In addition, microbiome on eczematous skin surface was sampled by swaps from each patient before the bath treatment, and after 9, 11 and 14 days of bath treatment. Thereafter, nucleic acids were extracted and the bacterial 16S rRNA gene was amplified via PCR for subsequent amplicon sequencing. Results showed a significantly reduced SCORAD over time of AD patients after daily synbiotic or prebiotic baths. Moreover, AD patients after daily synbiotic baths had a significantly improved pruritus and skin dryness and their bacterial microbiome was enriched by LAB. Taken together, a synbiotic bath is a promising topical skin application to alleviate AD.

Environmental Influences of High-Density Agricultural Animal Operation on Human Forearm Skin Microflora.

The human forearm skin microbiome ecosystem contains rich and diverse microbes, which are influenced by environmental exposures. The microbial representatives can be exchanged between human and environment, specifically animals, by which they share certain or similar epidermal microbes. Livestock and poultry are the microbial sources that are associated with the transmission of community-based pathogenic infections. Here, in this study, we proposed investigating the environmental influences introduced by livestock/poultry operations on forearm skin microflora of on-site farm workers. A total of 30 human skin swab samples were collected from 20 animal workers in dairy or integrated farms and 10 healthy volunteer controls. The skin microbiome was 16S metagenomics that were sequenced with Illumina MiSeq system. For skin microbial community analysis, the abundance of major phyla and genera as well as alpha and beta diversities were compared across groups. We identified distinctive microbial compositional patterns on skin of workers in farm with different animal commodities. Workers in integrated farms containing various animals were associated with higher abundances of epidermal Proteobacteria, especially Pseudomonas and Acinetobacter, but lower Actinobacteria, especially Corynebacterium and Propionibacterium. For those workers with frequent dairy cattle operations, their Firmicutes in the forearm skin microbiota were enriched. Furthermore, farm animal operations also reduced Staphylococcus and Streptococcus, as well as modulated the microbial biodiversity in farm workers' skin microbiome. The alterations of forearm skin microflora in farm workers, influenced by their frequent farm animal operations, may increase their risk in skin infections with unusual pathogens and epidermal diseases.

Regulation of Monospecies and Mixed Biofilms Formation of Skin Staphylococcus aureus and Cutibacterium acnes by Human Natriuretic Peptides.

Staphylococcus aureus and Cutibacterium acnes are common representatives of the human skin microbiome. However, when these bacteria are organized in biofilm, they could be involved in several skin disorders such as acne or psoriasis. They inhabit in hollows of hair follicles and skin glands, where they form biofilms. There, they are continuously exposed to human hormones, including human natriuretic peptides (NUPs). We first observed that the atrial natriuretic peptide (ANP) and the C-type natriuretic peptide (CNP) have a strong effect S. aureus and C. acnes biofilm formation on the skin. These effects are significantly dependent on the aero-anaerobic conditions and temperature. We also show that both ANP and CNP increased competitive advantages of C. acnes toward S. aureus in mixed biofilm. Because of their temperature-dependent effects, NUPs appear to act as a thermostat, allowing the skin to modulate bacterial development in normal and inflammatory conditions. This is an important step toward understanding how human neuroendocrine systems can regulate the cutaneous microbial community and should be important for applications in fundamental sciences, medicine, dermatology, and cosmetology.