HOUSTON (August 24, 2011) - A patient who had symptoms of inhalation anthrax infection and who eventually succumbed to the disease was actually infected by a different bacterial species that had acquired anthrax toxin genes. Within a matter of days, pathologists at The Methodist Hospital and scientists from two other institutions sequenced and analyzed the pathogen's genome, and determined it was not likely to be a bioterrorism weapon.
In an upcoming issue of the Archives of Pathology & Laboratory Medicine (now online), director of Center for Molecular and Translational Human Infectious Diseases Research at The Methodist Hospital Research Institute, James M. Musser, M.D., Ph.D., and colleagues report that the germ in this case is a strain of Bacillus cereus possessing a key plasmid and other genes the give Bacillus anthracis its virulent qualities. A plasmid is a small chromosome independent of the main bacterial chromosome, which -- under the right conditions - can be replicated and transmitted to other bacterial species.
"This patient had an unusually severe, rapidly progressing infection caused by Bacillus cereus, an organism not typically associated with fatal infections," said Musser. "We determined the whole genome sequence of this virulent bacterium within a few days after the patient was hospitalized. The investigative team was able to rule out a possible bioterrorism threat, determine the reasons for the strain's unusually high virulence, and correctly manage health care workers who may have been exposed. This work was important because it generated actionable intelligence using genome sequence information, moving use of this important technology into the clinic."
Musser also serves as the director of the Center for Molecular and Translational Human Infectious Disease Research at The Methodist Hospital Research Institute, and holds the Fondren Distinguished Endowed Chair