CD9 and infection: CD9 is a tetraspanin able to synchronize SDC1, fibronectin, and β1 integrins to allow efficient Staphylococcus aureus adhesion to several types of host cells [62], and infection by interfering with the capacity of neutrophils to kill Staphylococcus aureus [63], and in turn, Staphylococcus aureus induces SDC1 shedding in vitro through α- and β-toxins [64].