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Researchers Develop New Weapon Against Anthrax - 2002-08-21


Researchers have developed a new antibiotic that not only kills the anthrax strain used in last October's U.S. attacks but also could be used to rapidly detect areas, such as buildings, suspected of anthrax contamination.

Like humans, bacteria can become infected with viruses. Viruses that infect bacteria are called bacteriaphages.

Bacteriaphages are very specific to particular bacteria. Some of them slowly kill the bacteria they infect. Others are extremely virulent, like the bacteriaphage that invade anthrax. However, no bacteriaphage is strong enough to stop a galloping bacterial infection inside a human or animal.

That is until now. Researchers at Rockefeller University in New York isolated an enzyme or protein from the bacteriaphage for anthrax. The enzyme, known as PlyG lysin, binds to essential building blocks in the bacterium's cell wall, blocking anthrax's ability to multiply.

In a study appearing in the current issue of the journal Nature, senior author Vincent Fischetti and colleagues describe experiments with PlyG lysin.

"Where we mix the enzyme the [anthrax] bacterium in a test tube and showed that we could kill millions of organisms in a very short period of time," he said. "In seconds virtually, almost sterilizing the solution within a minute or two. We could also infect animals with the organism, bacillus, and give them the enzyme via the same route. Fifteen minutes later [we were] able to save over 75 percent of the animals whereas the control animals all died."

Mr. Fischetti thinks the drug would work as well in humans and with virtually no side effects, since the enzyme is specifically targeted to attack the anthrax infection.

For that reason, he also thinks it highly unlikely for the anthrax bacterium used in last year's attacks to develop resistance to the antibiotic since PlyG lysin is its natural enemy.

The researchers also describe how the enzyme can be used to rapidly detect the presence of anthrax contamination. Lead author Raymond Schuch says the new antibiotic can cut detection time to a fraction of what it now is.

"Current detection methods are probably too time consuming. They require growth of the prospective spores in the laboratory and some biochemical characterization and complex molecular characterizations," he said. "And it takes several days at least to identify the presence of bacillus anthracis. And we can essentially do that in about 10 to 15 minutes depending on the number of spores."

Mr. Schuch says detection can be done on site with a hand held light meter that detects glowing traces if anthrax is present.

When the PlyG lysin enzyme attacks anthrax, it rips open the bacteria, releasing molecules. Technicians suspected anthrax contamination would apply a substance that would make the molecules glow under the light meter.

The research was funded by an arm of the U.S. Department of Defense.

Because each bacterium has a bacteriaphage, the scientists say they could use the same approach they used to develop an antibiotic against anthrax to target other bacterial infections, including strep and menningitis.

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