The infectious form of the Chlamydia is the elementary body (EB). EB's have rigid outer membranes that help them survive for limited amounts of time outside of their host cells. The elementary bodies bind to receptors on host cells and initiate infection. Once the EB attaches to a susceptible host cell, it mediates its own internalization through pathogen-specified mechanisms that allow for the recruitment of actins with subsequent engulfment of the bacterium