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Last Updated: Friday, 24 October, 2003, 23:33 GMT 00:33 UK
Drug 'new weapon against bugs'
E coli
The researchers used the drugs to kill E.coli bacteria
Scientists are developing a new kind of antibiotics which could be used in the fight against drug-resistant bacteria.

The drugs kill bacteria by blocking the genetic messages they need in order to reproduce.

Research, published in the journal Science, found the chemical compounds killed E.coli bacteria, but not other cells in the body.

Doctors are keen to develop new drugs because bacteria are increasingly resistant to existing antibiotics.

If RNA polymerase is inhibited then the effects are likely to be lethal on the bacteria
Professor Ian Chopra, Antimicrobial Research Centre
It is hoped the drugs could be useful against types of bacterial organisms that cause diseases such as pneumonia and tuberculosis.

The compounds, known as CBR703, inhibit the action of RNA polymerase which is an enzyme needed in gene expression - translating DNA information into proteins.

Process

Researchers from Ohio State University studied the effects of a number of chemical compounds on E.coli bacteria.

They found that CBR703 inhibitors stopped gene expression in the bacteria.

Further tests showed they did this by preventing the formation of nucleotides - individual units that make up an RNA molecule - stopping RNA strands forming.

But they did not affect human cells. This is key to the successful development of new antibiotics, as some compounds could harm both bacteria and human cells.

Professor Irina Artsimovitc, who led the research, said: "It's a long way between knowing that something will kill bacteria and figuring out the exact process by which the bacteria is killed.

She added: "Once you have this information, you could predict if the inhibitor would be effective against a broad range of bacteria."

"Knowing how a new antibiotic acts on its target takes the process of making new drugs to a new level, allowing for better understanding of a drug's direct- and side-effects.

"Other antibiotics also inhibit RNA polymerase, but the ones in this study use a radically different inhibitory mechanism."

'Limitations'

Professor Ian Chopra of the director of the Antimicrobial Research Centre at the University of Leeds is carrying out research into whether RNA polymerase inhibitors could lead to antibiotics to treat the hospital-acquired infection MRSA.

He told BBC News Online: "If RNA polymerase is inhibited then the effects are likely to be lethal on the bacteria."

But he said previous research had found it hard to develop a consistently effective drug, and it was not clear if the US scientists were addressing the problem.

"Bacterial RNA polymerase is the target for an older class of antibiotics called the rifamycins.

"However, a limitation of drugs like rifampicin is the high frequency with which mutations conferring resistance arise by changes in the target RNA polymerase that prevent drug binding. "


SEE ALSO:
Pill 'could kill off superbugs'
22 Oct 03  |  Health
Antibiotics crisis 'looming'
28 Sep 03  |  Health


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