( Researchers have uncovered how members ...)Researchers find how some antibiotics kill bacteria

This new knowledge may help drug developers make slight changes to these antibiotics to make them more effective against drug-resistant strains of bacteria, said Irina Artsimovitch, a study co-author and an assistant professor of microbiology at Ohio State University.

The antibiotics studied belong to the rifamycin family. Until now, researchers believed that these antibiotics and their derivatives (there are at least a thousand) all killed bacteria in the same way.

But the new study used recent advances in X-ray imagery to obtain the highest resolution figures ever available of how rifamycins bind to their targets. With these new images, the researchers found ?for the first time - that these drugs remove a key component of the bacteria they attack. The researchers were also surprised to find that different rifamycins bring about this same result in slightly different ways.

"This is a major revision of how we thought these antibiotics functioned," Artsimovitch said. "The new molecular details help explain why bacteria that are resistant to one kind of rifamycin antibiotic might still be sensitive to another.

"That may help to narrow down the search for new synthetic derivatives to conquer resistance altogether."

The study appears in the current issue of the journal Cell.

Ryfamycin antibiotics are one of the first-line treatments for tuberculosis, a disease that is on the rise worldwide. The drugs are also relatively inexpensive to make, have a long shelf life and are nearly non-toxic to cells other than the pathogenic ones they target.

The problem with them, though, is the rampant development of bacterial resistance.

"There is a voluntary restriction on the use of rifamycins in treating infections other than tuberculosis and meningitis due to the fear of spread of resistant mutations," said Vl
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Source:Ohio State University