A simple course of antibiotics could relieve chronic back pain for up to 40% of sufferers, scientists claim.

Researchers have demonstrated a link between many cases of long-term back pain and infection by acne bacteria. One leading British expert described the discovery as “the stuff of Nobel prizes”.

Trial evidence indicates that pills to treat infection rather than surgery can bring an end to the misery of constant lower back pain.

If the results are confirmed, many thousands of people in the UK who suffer from chronic back pain could benefit.

Around four million Britons can expect to suffer from chronic lower back pain some time in their lives.

In the first of two papers published in the European Spine Journal, Danish researchers showed how bacteria invading the injury sites of slipped discs caused painful inflammation and damage to surrounding vertebrae.

Infection was previously thought to play only a small role in back pain. But nearly half the slipped disc patients studied by the scientists tested positive for bacterial infection.

The vast majority of infections were caused by Propionbacterium acnes, the bug responsible for acne.

P. acnes secretes an acid capable of dissolving bone, leading to painful bone swelling. The bugs may be to blame for up to 40% of all cases of chronic lower back pain, the researchers believe.

The second study tested a new form of treatment based on the discovery.

A group of 162 patients who had suffered from chronic back pain for more than six months following a slipped disc, and had signs of bone swelling, were either given a 100 day course of antibiotics or an inactive placebo drug.

The antibiotic treatment proved effective in 80% of cases, leading to significant reductions in pain and disability.

In their paper the scientists, led by Dr Hanne Albert, from the University of Southern Denmark, wrote: “Antibiotics should be considered as a treatment option for this special subgroup of patients with CLBD (chronic low back pain)..

“More confirmatory work in other populations and studies on improved protocols as well as the background science should be encouraged.”

Commenting on the results, neurosurgeon and spinal expert Peter Hamlyn, from University College London hospital, said: “The discoveries.. require us to reconsider our understanding of chronic low back pain.

“One of the commonest causes of disability in our communities, lost working days and ongoing pain, chronic low back pain is an international plague. More work needs to be done, but make no mistake this is a turning a point.. It is the stuff of Nobel prizes.”

But a note of caution was sounded by microbiologist Professor Laura Piddock, from the University of Birmingham, who stressed that antibiotics should only be used in cases where a bacterial cause of pain had been identified.

Inappropriate use of the drugs could help breed resistant bacteria.

“For this reason, physicians are encouraged to liaise with their consultant microbiologist colleagues for the most appropriate tests to carry out,” said Prof Piddock.