Overview of basic pathways potentially leading to shock, organ injury and death during B. anthracis infection. A. As Gram-positive bacteria, B. anthracis and its products (for example, cell wall and peptidoglycan) activate host defenses and inflammatory mediator release which are necessary for microbial clearance. However, if this response is excessive it may result in the development of shock, organ failure and death. B. B. anthracis also produces two exotoxins, lethal and edema toxins, which are capable of contributing directly to shock, organ injury and death via diverse mechanisms. C. Lethal and edema toxin also appear capable of subverting critical host defense systems and contributing to the pathogenesis of shock, organ injury and death by limiting microbial clearance. Other mechanisms not depicted in this figure, such as the activation of metalloproteases other than lethal factor, may contribute to shock and organ injury with B. anthracis as well (see text).