Staphylococcus epidermidis

Commensal bacterium of the normal skin microbiota, particularly abundant on facial skin and sebaceous gland-rich areas. Now recognised as a protective agent of the skin barrier: it produces fatty acids maintaining acidic skin pH, antimicrobial peptides (epidermin) inhibiting skin pathogens such as Staphylococcus aureus, and signals modulating the cutaneous immune response. Its depletion through excessive cleansing or antibiotic overuse can promote colonisation by pathogenic bacteria.