A novel flow cytometry-based assay for the quantification of Staphylococcus aureus adhesion to and invasion of eukaryotic cells

► Staphylococcus aureus-host cell interactions can be monitored using flow cytometry. ► Established techniques require pre-infection bacterial modifications. ► Such modifications can alter bacterial phenotype and bias results. ► We describe a novel flow cytometry adhesion and invasion assay. ► This assay does not require bacterial processing before infection.