How localized bacterial infections can turn into dangerous sepsis

We carry numerous bacteria on our skin, in our mouth, gut, and other tissues, and localized bacterial infections are common and mostly not harmful. Occasionally, however, a localized infection turns into dangerous systemic disease (sepsis), and scientists have new clues as to how that happens. A study published on March 20th in PLOS Pathogens shows that after intravenous injection of a million bacteria into a mouse, the resulting systemic disease is often started by only a single one of them.