Abstract
Our body is home to ten times more bacteria than it contains cells. Their activity is indispensable to our organism. Man and microbes form a veritable symbiosis, the complex mechanisms of which can only be deciphered with the help of molecular genetics.
But these bacteria also cause infectious and parasitic diseases: they kill around fifteen million people worldwide every year. To develop effective treatments and vaccines, we need to understand how they thwart our body's defenses, and decipher the rules of war and peace between microbes and us.