Bacillus anthracis is a spore forming Gram positive bacterial pathogen that causes the disease anthrax. Infection can occur via three different routes, gastro-intestinal, cutaneous, or inhalational. Bacterial spores introduced by each route have different levels of virulence and different hallmarks of disease. Systemic disease is associated with both toxemia and sepcemia; where two secreted toxins, lethal toxin and edema toxin, are responsible for toxemia, and encapsulation, which reduces phagocytosis by host defense cells, is responsible for sepcemia.
B. anthracis gained public notoriety when it was used as a bioweapon in the United States postal system in the autumn of 2001, but it has long been feared for its devastation of livestock herds and as an agent of zoonotic infectious disease from domesticated animals. Thanks to a highly effective animal vaccine, anthrax is very rare in the developed world. Yet because anthrax was considered a “beaten” disease, thanks to this efficacious veterinary vaccine, relatively little attention has been paid to the basic molecular mechanisms of how this bacterium causes disease. Thus, surprisingly little is known about how B. anthracis causes pathology (or pathogenesis) in an infected host.
Our laboratory’s goal is to elucidate the molecular mechanisms of B. anthracis pathogenesis and use this knowledge to guide research towards better means of detection and prevention of anthrax. We advance these goals by using techniques derived from bacterial genetics, molecular biology, biochemistry, immunology, and tissue culture and animal models of disease. Our past projects have focused on: 1) innate immune responses to B. anthracis spores, 2) the mechanisms of immune protection granted by vaccination with an experimental vaccine, and 3) the development of real-time small animal models of infection using bioluminescent bacteria that can be detected within infected animals (see photos and references). Future projects will expand upon these themes, but also include greater concentration on revealing the contribution of bacterial factors in B. anthracis pathogenesis.
Images of mice infected with an aerosol of bioluminescent Bacillus anthracis at the indicated times.