Skin Sentinels: Defensive Effector Molecules Produced by the Skin Microbiome

Purpose of ReviewThis review examines how the human skin microbiome contributes to defense against infection through its production of antimicrobial effector molecules. It explores the molecules involved in several classes of defensive mechanisms, the microbial and host interactions they influence, and their impact on pathogen colonization and virulence.Recent FindingsRecent research has highlighted the critical role of skin-resident microbes in producing diverse effector molecules, including bacteriocins, short-chain fatty acids, and autoinducing peptides. These compounds can inhibit pathogen growth directly, modulate host immune responses, and interfere with pathogen communication systems. Additionally, microbial commensals cooperate with the host to improve skin barrier function and immunity through production of ceramides and other small molecules.SummaryThe skin microbiome acts as an active partner in human health, deploying effector molecules that help defend against pathogens while supporting skin integrity. Loss of skin microbiome stability can negatively impact its protective capabilities, potentially opening the skin to infection by opportunistic pathogens. These findings emphasize the therapeutic potential of skin commensals and their products for treating skin diseases. Future research should focus on underexplored microbial taxa, antifungal activity, and the role of the skin virome to uncover novel strategies for supporting this critical community.