Relationship between skin fungal and bacterial microbiomes and skin pH.

OBJECTIVE: The present study investigated the relationship between the skin bacterial and fungal microbiomes and skin pH at sebaceous sites, namely, the forehead, cheek and upper chest. We also examined the relationship between the skin microbiome and transepidermal water loss (TEWL), which is an indicator of rough skin. METHODS: Thirty healthy Japanese subjects (15 females and 15 males) were enrolled as subjects. The forehead, cheek and upper chest were examined in August (summer) and February (winter). Skin surface samples were collected using the swab method, and the 16s rRNA and ITS regions were analysed using next-generation sequencing. Skin pH and TEWL were also assessed. RESULTS: The changes observed in the skin microbiome were associated with season-dependent changes in skin pH. An increase in skin pH at the forehead and cheek was associated with a higher relative abundance of Cutibacterium spp., a reduction in bacterial diversity, and a lower relative abundance of Staphylococcus spp. A decrease in skin pH at the upper chest was associated with a higher relative abundance of Malassezia restricta, a lower relative abundance of M. sympodialis and decrease in fungal diversity. Moreover, these changes were also associated with an increase in TEWL. CONCLUSION: The present results indicate that changes in skin pH are associated with changes in the skin bacterial and fungal microbiomes at sebaceous sites. The changes observed in the skin microbiome were also associated with rough skin.

OBJECTIF: La présente étude a examiné la relation entre les microbiomes bactériens et fongiques de la peau et le pH de la peau des sites sébacés, à savoir le front, la joue et la partie supérieure du thorax. Nous avons également examiné la relation entre le microbiome cutané et la perte d'eau transépidermique (transepidermal water loss, TEWL), qui est un indice de rugosité cutanée. MÉTHODES: Trente sujets japonais en bonne santé (15 femmes et 15 hommes) ont été inclus en tant que sujets de l'étude. Le front, la joue et la partie supérieure du thorax ont été examinés en août (été) et en février (hiver). Des échantillons de surface cutanée ont été prélevés par écouvillonnage et les régions de l'ARNr 16s et ITS ont été analysées par séquençage à haut débit. Le pH de la peau et la TEWL ont également été évalués. RÉSULTATS: Les changements observés dans le microbiome cutané étaient associés à des modifications du pH de la peau dépendant de la saison. Une augmentation du pH de la peau au niveau du front et de la joue était associée à une plus grande abondance relative de Cutibacterium spp. et à une réduction de la diversité bactérienne, ainsi qu'à une plus faible abondance relative de Staphylococcus spp. Une diminution du pH de la peau au niveau de la partie supérieure du thorax était associée à une abondance relative plus élevée de Malassezia restricta et à une abondance relative plus faible de M. sympodialis, ainsi qu'à une diversité fongique. De plus, ces changements ont également été associés à une augmentation de la TEWL. CONCLUSION: Ces résultats indiquent que les modifications du pH de la peau sont associées à des modifications des microbiomes bactérien et fongique de la peau au niveau des sites sébacés. Les changements observés dans le microbiome de la peau étaient également associés à une rugosité de la peau.

The Microbiome in Comedonal Contents of Inflammatory Acne Vulgaris is Composed of an Overgrowth of Cutibacterium Spp. and Other Cutaneous Microorganisms.

Background: Acne vulgaris (acne) and cutaneous resident microorganisms are considered to be closely related. However, the bacterial and fungal microbiota in the comedonal contents of inflammatory acne lesions have not yet been investigated in detail. Purpose: To clarify the relationship between cutaneous microorganisms and acne, we examined the microbiome in the comedonal contents of inflammatory acne and on the facial skin of patients with acne using 16s rRNA and ITS gene sequencing with a next-generation sequencer (NGS). Patients and Methods: Twenty-two untreated Japanese acne outpatients were examined. The comedonal contents of inflammatory acne lesions on the face were collected using a comedo extractor. Skin surface samples from facial skin were collected using the swab method. Results: The results obtained revealed that the predominant bacteria in the comedonal contents of inflammatory acne were Cutibacterium spp. (more prominent in areas with large amounts of sebum), while those on the skin surface were Staphylococcus spp. Malassezia spp., particularly Malassezia restricta, were the predominant fungi in both the comedonal contents of inflammatory acne and on the skin surface. The bacterial microbiome in comedonal contents exhibited stronger metabolic activity, including the production of enzymes related to acne, than that on the skin surface. Conclusion: These results indicate that acne is an inflammatory disease involving the overgrowth of Cutibacterium acnes and other cutaneous resident microorganisms, including Malassezia spp.

Correction: Water pre-filtration methods to improve environmental DNA detection by real-time PCR and metabarcoding.

[This corrects the article DOI: 10.1371/journal.pone.0250162.].

Water pre-filtration methods to improve environmental DNA detection by real-time PCR and metabarcoding.

Environmental DNA (eDNA) analysis is a novel approach for biomonitoring and has been mostly used in clear water. It is difficult to detect eDNA in turbid water as filter clogging occurs, and environmental samples contain various substances that inhibit the polymerase chain reaction (PCR) and affect the accuracy of eDNA analysis. Therefore, we applied a pre-filtration method to better detect the fish species (particularly pale chub, Opsariichthys platypus) present in a water body by measuring eDNA in environmental samples containing PCR inhibitors. Upon conducting 12S rRNA metabarcoding analysis (MiFish), we found that pre-filtration did not affect the number or identities of fish species detected in our samples, but pre-filtration through pore sizes resulted in significantly reduced variance among replicate samples. Additionally, PCR amplification was improved by the pre-filtration of environmental samples containing PCR inhibitors such as humic substances. Although this study may appear to be a conservative and ancillary experiment, pre-filtration is a simple technique that can not only improve the physical properties of water, such as turbidity, but also the quality of eDNA biomonitoring.