A new article published in Pediatric Research stated that the skin is the outermost layer of defense against a constant encounter with environmental microbes and antigens. While the majority of these microbes are harmless, a few specific ones are potential pathogens.

Throughout the life span, newly colonizing microbial species come across the existing skin microbiome, conferring a competitive exclusion of potential pathogens. Additionally, host-specific factors or intrinsic factors – release of sebum, sweat, and small antimicrobial compounds secreted by subcutaneous glands, impose selective pressure on certain microorganisms.

Previously, the knowledge of these communities was based on culture-dependent techniques, but recent advances in culture independent methodologies, for example, next generation sequencing, are elucidating diverse communities of bacteria, fungi and viruses.

This article reported that the majority of cutaneous microbes are bacteria; however, some sites also have a relatively high membership of resident fungi—collectively termed the mycobiome. Disordered fungal colonization of the skin has been associated with various disorders such as dermatophytosis, atopic dermatitis and seborrheic dermatitis. However, the knowledge of the skin mycobiome remains extremely limited.

Nonetheless, cutaneous fungi play important roles in host health, including colonization-resistance against pathogens and in facilitating immune development and maintenance of the host. During the neonatal period, the fungal communities remain relatively static—in both, preterm and term-born infants. Host-specific factors largely shape the mycobiome in neonates and infants. Furthermore, the skin mycobiome is important to immune development during early life and influences the host’s vulnerability to neonatal sepsis.

Source: Pediatric Research. 2020 Aug; 88(2): 153–154. Published online 2020 May 14. doi: 10.1038/s41390-020-0959-6