The anthrax attacks of last fall rattled an already shaken nation and presented public health officials with two weighty problems: detecting spores of the deadly bacterium, and treating exposed and infected individuals. Luckily, the strain that was disseminated yielded to standard drugs. Had it been resistant, the outcome might have been far worse. Scientists have thus been searching fervently for better ways to identify and tackle anthrax. Now a new antibiotic could help on both fronts.
Researchers writing today in the journal Nature report that an enzyme extracted from a virus that naturally infects the anthrax bacterium assaults the bug in such a way that it would be nearly impossible to create strains resistant to its effects. Specifically, Raymond Schuch of the Rockefeller University and his colleagues found that the enzyme--known as PlyG lysin--targets anthrax bacteria and rapidly ruptures them. Indeed, just drops of it can apparently destroy a test tube full of the bugs on the spot. "This enzyme is almost as effective as pouring bleach over these organisms," Schuch remarks. "There is no other known biological agent that kills this quickly." Importantly, PlyG does not attack other cells. "This is beneficial because, unlike antibiotics, this kind of therapy would not kill off useful bacteria in our bodies and thus would have few or no side effects," he explains. Injections of PlyG saved roughly 80 percent of mice infected with a lethal bacterium closely related to anthrax.
The researchers further note that PlyG could help to identify areas of potential anthrax contamination. It seems that when bacteria invaded by the viral enzyme rupture, they release a molecule known as ATP, which can be detected in minutes with the aid of a glowing reagent and a handheld light meter. Additional work is needed before the antibiotic is developed. But "given these promising results," write M. J. Rosovitz and Stephen H. Leppla of the National Institute of Dental and Craniofacial Research in an accompanying commentary, "we expect to see rapid moves to test the use of bacteriophage lysins in detecting and treating other bacterial infections."