Sending germs to fight bugs

Pitting one germ against the other offers new methods of fighting infection without the use of antibiotics, researchers said this week.

One method uses a deadly enzyme made by viruses called bacteriophages that precisely execute bacteria, and another uses compounds made by one bacteria to shut down another without actually killing it.

Each illustrates potential new ways to fight the growing problem of superbugs - bacteria that have mutated and gained the ability to resist most or even all of the antibiotics used against them.

The new technique might also work against biological agents such as anthrax, the researchers told a meeting sponsored by the American Society for Microbiology.

A single squirt of the bacteria-killing enzyme could help to keep an infected person from sneezing out bacteria for up to a week, said Dr Vincent Fischetti, of Rockefeller University in New York.

"These are enzymes that, basically, punch a hole in the bacteria and cause them to explode" he said.

Researchers have used them to decontaminate animals of pesky bacteria such as Group A streptococci and staphylococci.

"We can eliminate these organisms from the noses of these animals," said Dr Fischetti.

Scientists tried it intravenously against the anthrax bacillus. "We could save 90 per cent of the animals with a single dose of the enzyme."

The researchers are planning tests in mice, monkeys and perhaps rabbits, and will use the results to seek permission to test the enzyme on human volunteers. "These enzymes work instantly," Dr Fischetti said.

They could be sprayed into the nose in a saline buffer, he said.

Another researcher, Dr Richard Novick, and colleagues at New York University's medical school, looked specifically for ways to stop bacteria from attaching to and killing cells in the body.

They isolated peptides - short pieces of proteins - that regulate this behaviour by bacteria.

"We happen to have hit on one of these that provides an Achilles heel of the organism," Dr Novick said.

"We can disarm the organism ... simply by introducing one of these inhibitory factors."

Staphylococcus aureus - one of the worst causes of infections caught in hospitals - have evolved into four strains, each with a different version of this peptide.

"Remarkably and conveniently for us, the peptide produced by any one of the subspecies blocks activation of the virulence response by any of the others," Dr Novick said.

Researchers created a version of the peptide that blocks all four and are now trying to improve it so it works even more broadly and lasts longer.

- REUTERS