Gene project could unlock powerful new antibiotics

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The Independent Online

Scientists have opened the door to the discovery of new and more powerful antibiotics by decoding the genes of a common microbe that lives in the soil.

Scientists have opened the door to the discovery of new and more powerful antibiotics by decoding the genes of a common microbe that lives in the soil.

The bacterium, called Streptomyces, is already the source of two thirds of the naturally produced antibiotics used by doctors but its genes may hold information leading to the production of many more drugs.

Finding new antibiotics to replace those rendered useless by drug-resistant infections is one of the most pressing goals of medical science. Some scientists predict that the day could soon arrive when patients suffering from some common bacterial diseases will become untreatable.

A team of British scientists, led by Sir David Hopwood of the John Innes Centre in Norwich, took nearly five years to sequence the entire 8.7 million DNA "letters" that make up the genetic book of Streptomyces coelicolor, a bacterium that gives soil its earthy smell.

The scientists, who included a DNA sequencing team from the Wellcome Trust Sanger Institute near Cambridge, found that the microbe had more than 7,800 genes – making it the largest microbial genome so far deciphered – and that about 5 per cent of those genes were involved in producing so-called secondary metabolites, which include antibiotics.

Stephen Bentley, the lead author of the study published in the journal Nature, said the complexity of the Streptomyces genome enabled the microbe to wage a form of chemical warfare against other competing microbes in the ground.

"They're big in the import-export business, with enzymes secreted to degrade substances in the soil. This bacteria is like the boy scout of bacteria – it's prepared for any eventuality," Dr Bentley said.

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