[ODP-040] Growth inhibition of Staphylococcus aureus by interaction of commensal bacteria and free fatty acids
Commensal bacteria have been shown to promote skin health by restricting pathogen colonization and the human skin protects against pathogens by producing innate immunity components, antimicrobial peptides and free fatty acids (FFAs). FFAs are well known as potent antimicrobials, however microbes such as Staphylococcus aureus which found in the anterior nares of approximately 30% of the human population display a various mechanism to prevent or mitigate FFAs toxicity. S. aureus is one of the most problematic causes of a range of infections from mild skin infections to lethal bacteremia. We hypothesized that FFAs antagonize S. aureus through affecting bacterial interaction between S. aureus and commensal bacteria.We found that the Corynebacterium sp. which is one of the normal residents of human skin and mucosa inhibited S.aureus growth during side-by-side cocultivation on agar plate in the presence of subinhibitory concentration of FFAs. The growth inhibition was observed in the presence of unsaturated FFAs such as oleic acid but not saturated FFAs like stearic acid. These results suggested that commensal Corynebacterium sp. prevent S. aureus growth cooperating with host FFAs.