Infection of HeLa and mucin-producing LS174T cells with EPEC2 (espZ and tir) and EPEC1 (tir) showed accumulation of F-actin underneath the attached bacteria, confirming that EPEC only needs the effector Tir to induce the actin-pedestals during infection of epithelial cells in vitro. This evidence concerns the gene MUC5AC and infection.