Diarrheal diseases are a major global health problem and are ranked 5th among the leading causes of death in the world, according to the World Health Organization. Bacterial pathogens that cause diarrheal diseases have a specialized transport system, known as the type III secretion system, which injects virulence factors into the host cells. These virulence factors subvert the normal pathways of the host cells and promote bacterial replication and transmission. The research in our laboratory is focused on characterizing this highly important bacterial transport system by using state-of-the-art microbiology, molecular biology, biochemical, and biophysical approaches. The results of our work will have important implications for drug discovery and vaccine design against bacterial pathogens and possible implications for targeted drug delivery.