Bacterial adhesion and entry into host cells.

Successful establishment of infection by bacterial pathogens requires adhesion to host cells, colonization of tissues, and in certain cases, cellular invasion-followed by intracellular multiplication, dissemination to other tissues, or persistence. Bacteria use monomeric adhesins/invasins or highly sophisticated macromolecular machines such as type III secretion systems and retractile type IV pili to establish a complex host/pathogen molecular crosstalk that leads to subversion of cellular functions and establishment of disease.