Microbiotec'17 - Congress of Microbiology and Biotechnology 2017Background: Staphylococcus epidermidis is a commensal inhabitant of healthy human skin and mucosae. However, when external barriers, such as the skin, are damaged, the bacterium gains accesses into the bloodstream and emerges as an opportunistic pathogen. S. epidermidis can originate important infections such as medical device-associated bloodstream infections. This is mainly due to its ability to attach and form biofilms on the surface of vascular catheters. Hence, due to the clinical relevance of S. epidermidis medical device-associated bloodstream infections, human blood is frequently used as an ex vivo model, to mimic the environment encountered by the bacterium and study its behavior. An important limitation in the use of human blood is the availability of donors and the considerable quantity of blood necessary. As any other biological resource, the use of blood shall be reduced to a minimum and, thus, our goal was to test the influence of different volumes of human blood on the stability of S. epidermidis gene expression and on bacterial culturability.This work was supported by national funds (FCT) by the strategic project of UID/BIO/04469/2013 and by BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020. SB had an individual fellowship (UMINHO/BD/15/2016) supported by the Doctoral Program in Chemical and Biological Engineering (NORTE-08-5369-FSE-000052 Operation) by NORTE 2020 Program and co-funded by European Social Fund.NC is an Investigador FCT.info:eu-repo/semantics/publishedVersio