Context and rationale for studying bacterial pathogenesis. Overview of the steps involved in bacterial infection. Bacterial pathogens cause a wide range of disease at a wide range of body sites! Something that causes disease in the intestine is not likely to cause an infection in the skin. Bacterial infection is a major cause of death ww particularly in low income countries. Summer 2011: european e. coli hemorrhagic colitis outbreak, caused by a newly emerged strain of bacteria with a unique combination of virulence factors (never seen before) Notably, old threats can re-emerge: there was an outbreak of the plague in madagascar last year. Abx resistance limits our ability to treat bacterial infections. Presently, there are bacteria that are resistant to every type of abx used in clinic. Compounding this problem is the fact that large drug companies have essentially stopped developing abx. The drug pipeline for new abx is virtually dry .