After several years at the Pasteur Institute working on protein structure and DNA-protein interactions, I had the chance in the mid-1980s to change projects and start studying bacterial pathogens. With my colleague Brigitte Gicquel, I identified two models to work on: the bacterium that causes tuberculosis, a disease that infects about 9 million people per year, or Listeria, a bacterium that causes disease in some 2,500 people in the United States annually, with only about 500 deaths per year. I chose Listeria.
To me, it seemed a perfect model organism. Unlike Mycobacterium tuberculosis, Listeria appeared easy to manipulate genetically, it grew fast, and had an interesting life cycle. At the time, many studies were carried out on extracellular pathogens and it seemed valuable to investigate intracellular bacterial pathogens. As knowledge accumulated, I marveled at how, once Listeria enters a cell, it appears to don a cape made of the host ...
