Yoghurt bacteria 'fights' superbugs

The bacteria were able to inhibit MRSA

A bacterium related to those found in "bio" yoghurts may be able to restrict the growth of the so-called "superbug" MRSA.

Laboratory research, reported in New Scientist, found that a strain of the Lactobacillus fermentum bacterium, had an effect on the spread of the more dangerous Staphylococcus aureus.

This strain is similar, although not identical, to those contained in many varieties of "live" yoghurts which are marketed as a way of maintaining digestive health.

Scientists coated small sheets of silicone with Staphylococcus aureus, and half also recieved a coating of the Lactobacillus bacteria.

These were then implanted under the skin of rats and left for a few days.

They discovered that those given a sheet with only Staphylococcus had developed sores filled with pus - a sign of serious developing infection.

Those given both types of bacteria had clean and healthy wounds.

Gregor Reid, one of the microbiologists carrying out the research at the University of Western Ontario, is not sure why Lactobacillus appears able to inhibit the growth of the more dangerous bacteria.

He believes it may secrete a protein which stops Staphylococcus binding onto human cells.

In addition, simply slowing down rather than destroying the Staphylococcus may help prevent strains becoming more resistant to antibiotic treatment.

Antibiotics work by killing the bacteria, so the weaker strains are more likely to perish, leaving any which have developed resistance to thrive.

Survival of the toughest

Over time, this means powerful strains have the right environment to survive.

In immunosuppressed patients, or those weakened by illness or surgery, antibiotic resistant bacteria can be dangerous. Many of these strains are present in the UK's general hospitals.

A treatment which inhibits rather than kills bacteria is less likely to speed the arrival of resistant strains.

Dr Reid told New Scientist that using "live" was an option: "In patients facing death or amputation it is worthy of investigation."

The potential of using harmless bacteria such as Lactobacillus has been investigated by other doctors as a potential treatment for life-threatening diarrhoea, particularly in children.

Dr James Soothill, a consultant microbiologist at Great Ormond Street children's hospital in London, said that the protective effect of particular strains in the vagina was well known.

He told BBC News Online: "They produce acid which in turn produces an environment in which it is difficult for other, more harmful, bacteria to live.

"There is certainly a lot of interest in using live bacteria for a wide variety of applications."