Streptococcus equi ssp. zooepidemicus (SEZ) is a zoonotic pathogen that infects mainly horses and is additionally associated with endocarditis, meningitis, and respiratory diseases in humans. SEZ can adhere to human cells, but underlaying pathomechanisms are not yet clarified. Assuming that systemic infections require multifactorial interactions with the cell surface, we aim to identify the bacterial adherence factors, which mediate bacterial cell attachment during an endocarditis infection. Primary human cardiac endothelial cells (HCMEC) serve as model cells to analyse SEZ adherence to the vasculature. We performed cell culture infection analyses and microscopically quantified SEZ-attachment to HCMEC at various incubation times and bacterial multiplicity of infections (MOI). In order to mimic the altered shear force conditions during heart valve infection, we established a microfluidic pump system that enables the culture of cells under a defined medium flow. In this system, a pneumatic pump presses medium over a confluently grown HCMEC layer, which was seeded onto specialized microslides allowing microscopic visualization. Immuno fluorescence staining confirmed SEZ adherence to HCMEC in a standardized cell culture infection and at shear forces of 5 and 10 dyn/cm2. In addition, a surface expression profile of selected endothelial receptors of primary HCMEC in static cell culture and after 48 h of flow cultivation was determined by flow cytometry. At later project stages, a Transposon library will be used to identify new bacterial adherence factors comparing the sequences of the bacterial in- and output pools via Transposon directed insertion sequencing (TraDIS).