Bacteria mimics anthrax in Texas patient

Houston scientists have determined that a patient admitted to Methodist Hospital with symptoms of inhalation anthrax had not contracted the disease at all, but instead had been infected by a different bacterium that was abnormally producing anthrax toxin.

When the 75-year-old patient was admitted to the hospital and then died three days later, doctors believed that he might have been the victim of a form of bioterrorism, but it was found that he had actually been infected with Bacillus cereus, which usually causes no illness in humans, according to

A team led by Dr. James Musser of Methodist Hospital, along with members from the Methodist Hospital Research Institute and the Chicago-based Center for Biodefense and Emerging Infectious Diseases, searched through the genes of the B. cereus in the patient for signs that it may have been deliberately altered by humans intending to kill.

"This strain lacked unusual genetic factors likely to be present in an engineered bioterrorism agent," Musser said, reports. "It lacked an unusual spectrum of toxins and diverse antibiotic-resistance genes that would have made it harder to treat – there were no signatures of man-made genetic alterations."

The team discovered that B. cereus, in this case, had developed plasmids with the same genes that make Bacillus anthracis, the bacterium that causes anthrax, so deadly.

Plasmids exist separately from the bacterium’s chromosomes and contain segments of its DNA. Scientists know that plasmids can be shared from one bacterium to another and that they play critical roles within the bacterial lifecycle, including spreading the genes that produce toxins and confer resistance to anti-bacterial agents, reports.

According to an online report that appears in the journal Archives of Pathology and Laboratory Medicine, tests showed that the Methodist Hospital case was an isolated incident and no one else was infected.

Muller and his team used genomic sequencing, a relatively new technique, to rapidly create a map of the genes on the bacterium’s chromosome, allowing the researchers to discover the cause of the man’s illness more quickly than if they had used conventional methods.

"Until recently, it would have taken months or years to do what we did in days," Musser said, according to "We can do the genomic sequencing and analysis even faster with the next generation of genomic sequencers."