Metabolites derived from bacterial isolates of the human skin microbiome inhibit biofilm formation.

UNLABELLED

The human skin microbiome is a diverse ecosystem that can help prevent infections by producing biomolecules and peptides that inhibit growth and virulence of bacterial pathogens. is a major human pathogen responsible for diseases that range from acute skin and soft tissue infections to life-threatening septicemia. Its ability to form biofilms is a key virulence factor contributing to its success as a pathogen as well as to its increased antimicrobial resistance. Here, we investigated the ability of bacterial skin commensals to produce molecules that inhibit biofilm formation. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identified 77 human skin microbiome bacterial isolates from and genera. Metabolites from cell-free concentrated media (CFCM) from 26 representative isolates were evaluated for their ability to inhibit biofilm formation by both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains. CFCM, derived from most of the isolates, inhibited biofilm formation to varying extents but did not inhibit planktonic growth of . Size fractionation of the CFCM of three . isolates indicated that they produce different bioactive molecules. Cluster analysis, based on either MALDI-TOF mass spectra or whole-genome sequencing draft genomes, did not show clear clusters associated with levels of biofilm inhibition among strains. Finally, similar biosynthetic gene clusters were detected in all strains analyzed. These findings indicate that several bacterial constituents of the human skin microbiome display antibiofilm activity, warranting further investigation on their potential as novel therapeutic agents.

IMPORTANCE

The skin is constantly exposed to the environment and consequently to numerous pathogens. The bacterial community that colonizes healthy skin is thought to play an important role in protecting us against infections. is a leading cause of death worldwide and is frequently involved in several types of infections, including skin and soft tissue infections. Its ability to adhere to surfaces and produce biofilms is considered an important virulence factor. Here, we analyzed the activity of different species of bacteria isolated from healthy skin on biofilm formation. We found that some species of and can reduce biofilm formation, although a generally lower level of inhibitory activity was observed compared to isolates. Among isolates, strength of activity was dependent on the strain. Our data highlight the importance of mining the skin microbiome for isolates that could help combat skin pathogens.