New way of killing dangerous bacteria like the ones which cause anthrax and pneumonia

Sep 7 2004

Researchers from Rockefeller University, New York, have developed a new way of killing dangerous bacteria like the ones which cause anthrax and pneumonia, using products from a virus, according to new research presented today Tuesda at the Society for General Microbiology’s 155th Meeting at Trinity College Dublin.

The new bug-smashing technique uses the bacteria’s own natural enemies, tiny viruses called bacteriophages (or phages), which can infect bacterial cells. The phages make thousands of copies of themselves inside infected bacteria, but then need to dissolve the bacteria’s cell wall to get out and infect other bacterial cells.

“We realised that bacteria have no effective natural defences against these phages once they have been infected,” says Professor Vincent Fischetti of Rockefeller University. “After infection, the phages make an enzyme to dissolve the bacterial cell walls for release and we found that we could use the same enzyme to attack and kill the disease bacteria responsible for pneumonia, anthrax or strep throat.”

The enzymes work on contact, killing the disease bacteria instantly, but without harming other friendly types of bacteria. This offers huge advantages over conventional antibiotics, which indiscriminately kill most bacteria, including our useful ones, and which can lead to disease resistance building up if used too frequently.

“About half of us normally carry disease bacteria in our nose or throat, but without symptoms, which form the only reservoir for these organisms in the environment, allowing them to travel from person to person until they are able to cause infection in the right individual,” says Prof Fischetti. “Removing these bacteria from people in hospitals, day care centres and nursing homes could have a major impact on disease outbreaks amongst vulnerable people in these settings.”

The novel technique offers medical workers an opportunity to control disease bacteria in a completely new way. So far no resistance has been found to the enzymes, but if it were to occur it would be very rare, much rarer than antibiotic resistance. The enzymes successfully kill antibiotic-resistant bacteria that are causing a major problem in hospitals and nursing homes.

“We now have enzymes that kill all bacteria of a particular type, called Gram-positive bacteria, of the major disease-causing organisms, including bacteria for strep throat, pneumonia, neonatal meningitis, endocarditis and anthrax,” says Prof Fischetti. “Since we have never found any resistance to the enzymes, they can be used safely, long term, even to kill recurrent infections.”

In addition, the scientists are currently carrying out clinical trials of an enzyme which can specifically kill anthrax in the blood. This could be used during a terrorist attack or emergency to save the lives of exposed individuals.