Novel volatiles of skin-borne bacteria inhibit the growth of Gram-positive bacteria and affect quorum-sensing controlled phenotypes of Gram-negative bacteria

The skin microbiota is import for body protection. Here we present the first comprehensive analysis of the volatile organic compound (VOC) profiles of typical skin-resident corynebacterial and staphylococcal species. The VOC profile of Staphylococcus schleiferi DSMZ 4807 was of particular interest as it is dominated by two compounds, 3-(phenylamino)butan-2-one and 3-(phenylimino)butan-2-one (schleiferon A and B, respectively). Neither of these has previously been reported from natural sources. Schleiferon A and B inhibited the growth of various Gram-positive species and affected two quorum-sensing-dependent phenotypes - prodigiosin accumulation and bioluminescence - of Gram-negative bacteria. Both compounds were found to inhibit the expression of prodigiosin biosynthetic genes and stimulate the expression of prodigiosin regulatory genes pigP and pigS. This study demonstrates that the volatile schleiferons A and B emitted by the skin bacterium S. schleiferi modulate differentially and specifically its interactions with members of diverse bacterial communities. A network of VOC-mediated interspecies interactions and communications must be considered in the establishment of the (skin) microbiome and both compounds are interesting candidates for further investigations to better understand how VOCs emitted by skin bacteria influence and modulate the local microbiota and determine whether they are relevant to antibiotic and anti-virulence therapies.