Importance of preserving the resident microflora of the skin to improve immunological response

[...]by means of pattern recognition receptors, such as Toll-like receptors, mannose receptors, and the nucleotide-binding oligomerization domain-like receptor (NOD receptors), keratinocytes continuously sample the microbiota colonizing the skin surface.2 In this view, skin microbiota must be considered as one of the main factors influencing the response to infection since it has been recognized as a necessary element of immunity, being able to regulate the immune response of the host and also to maintain homeostasis.3 Hands represent a primary vector for infection transmission, including the so actual COVID-19 infection. Handwashing minimally impacts on microbiota healthiness but the widespread use of disinfectants, especially during COVID-19, has been reported to be detrimental to hand’s microbiota homeostasis and antibacterial potential.4 This is the consequence of the reduction of species richness leading also to the alteration of skin structure (eg, barrier, hydrolipidic film) and functions such as immune response, colonization resistance (due to the presence of triclosan in hand sanitizers) but also the lowering of the production of antimicrobial peptides (dermcidin, LL-37) and exacerbation of inflammatory milieu. [...]the immune response of the skin could be preserved.