FROM A COMMENSAL TO A PATHOGEN – TWO FACES OF STAPHYLOCOCCUS EPIDERMIDIS

Abstract Staphylococcus epidermidis is a commensal organism and the most abundant constituent of the healthy human skin and mucous membranes micrbiota. It is well adapted to colonize and evade human antimicrobial barriers. Staphylococcus epidermidis not only competes with potentially harmful pathogens, but also produces a plethora of proteins supporting host natural defenses. At the same time, S. epidermidis is an opportunistic pathogen recognised as one of the leading causes of healthcare-associated infections. S. epidermidis is mainly responsible for bloodstream infections and other biomedical device-related infections. Hospital strains of S. epidermidis form protective biofilm and are characterised with antibiotic resistance. 1. Introduction. 2. Staphylococcus epidermidis as a commensal organism. 2.1. Origin of S. epidermidis . 2.2. Human skin as S. epidermidis environment. 2.3. Adaptation mechanisms of S. epidermidis . 2.4. Mechanisms of supporting skin’s antimicrobial defences. 2.5. Influence on activity of host cells. 3. S. epidermidis as a pathogen. 3.1. Biofilm and virulence factors. 4. Summary