Exposure to antibiotics linked to resistance

LONDON, Feb 9 (Reuters) Exposure to common antibiotics used to treat respiratory infections can increase resistance to the drugs, Belgian scientists said today.

The emergence of bacteria that do not respond to antibiotics is a major health problem. Overuse of the drugs has been blamed for the development of so-called superbugs which are resistant to the most powerful antibiotics.

But trying to prove it has been difficult.

In a study that looked at the impact of the drugs on individuals, Professor Herman Goossens of University Hospital in Antwerp showed a single course of a drug can lead to a build-up in resistance.

''Exposure to the antibiotics was the strongest variable and this was independently associated with resistance,'' said Goossens, a microbiologist.

He and his team analysed the use of macrolide antibiotics, widely used drugs in primary care to treat ear, throat and lung infections.

The scientists, who reported the findings in The Lancet medical journal, compared two macrolide antibiotics -- clarithromycin and azithromycin -- against a placebo, or dummy pill, on more than 200 healthy volunteers.

They took several samples of bacteria from the volunteers before and up to six months after giving them antibiotics. The levels of resistant bacteria rose following the drug treatment.

''We have clearly defined, at the individual level, the direct effect of antibiotic use in selecting resistant organisms,'' Goossens told Reuters.

Stephanie Dancer of Southern General Hospital in Glasgow, Scotland, said the scientists should be commended for their careful approach.

''We now have strengthened evidence for the links between antibiotic use and resistance,'' she said in a commentary in the journal.

REUTERS AKJ PM0823