Viruses to destroy disease

The viruses can kill bacteria

Scientists are harnessing the destructive power of tiny viruses to combat potentially deadly bacterial diseases.

They have already discovered a virus that can destroy the E. coli bacterium that can cause severe food poisoning.

They are now working on other viruses which may have the potential to kill off the bacteria that cause other serious diseases.

The researchers hope this approach could ultimately lead to new drug treatments for diseases such as pneumonia, cholera and Lyme's disease.

New types of antibiotic are badly needed as many diseases are developing growing resistance to currently available drugs.

Cell walls

The small bit of protein responsible could be mimicked by a pharmaceutical company

Dr Douglas Struck

The researchers, from the Texas Agricultural Experiment Station, found that a protein contained within a small virus known as a Q-beta phage does the same thing to bacterial cell walls as antibiotics.

It blocks the ability of the cell to make its tough outer wall so bacteria blow up or destroy themselves rather than divide into more cells. Dead bacterial cells means an end to the illness.

Biochemist Dr Ry Young said: "Basically they let the cell commit suicide by dividing without making a new cell wall."

Fellow researcher Dr Douglas Struck, a genetics professor, said the discovery could open up a fertile new field of research.

He said: "Ideally, the small bit of protein responsible could be mimicked by a pharmaceutical company and a drug could be made to be general against many bacteria, or specific against a certain pathogen.

"Even better, it could easily be changed to overcome resistance."

Dormant bundles

Phages are not the same type of viruses that infect humans, animals and plants.

It looks like small phages are a gold mine for protein antibiotics

Dr Ing-Nang Wang

Essentially, they are dormant bundles of DNA or RNA in protein coats until they come into contact with bacteria.

They then go into action, replicating within the bacterial cell and, after only a few minutes, exploding it.

Lead researcher Dr Ing-Nang Wang said: "As bacteria's natural enemies, their potential as sources for ways to kill bacteria should have been thoroughly explored long ago but it is only now, with the emerging world-wide crisis in antibiotic resistance, that phages are finally gaining attention in their own right.

"It looks like small phages are a gold mine for protein antibiotics."

The Texas team has already discovered a second phage that makes a protein antibiotic. They are currently working on a third.

Encouragingly, each phage appears to make a different type of cell wall poison, so each is a potential model for a different type of new antibiotic drug.

The research is published in Science magazine.