About bacterial invasion of epithelial cells, we found that Cdc42 and Arp2/3 up-regulated in Listeria infection pathway and Salmonella infection pathway, followed by ILK up-regulation in staphylococcus aureus infection pathway, jointly promoted actin production and polymerization, at last enhanced internalization and vacuole formation. The gene discussed is CDC42; the disease is staphylococcus aureus infection.