The system, developed by Bengt Jeppsson, professor of surgery at University Hospital in Malmo, feeds patients with live bacteria normally found in cheeses and fermented vegetables, in order to encourage their growth in the intestine. At least six people who were in intensive care, and some children with recurrent intestinal infections, have been cured by the use of such "probiotic" treatment. A total of 300 are now being tested in clinical trials to last through 1999.
"It's a completely new concept," said Prof Jeppsson. "The lactobacillus [is] important for healing ulcers and other wounds in the bowel. When we artificially increase the amount of them in the bowel, they supplant the pathogenic bacteria - which also means that you don't have to use antibiotics."
Most people think of bacteria as harmful, an image encouraged by adverts for household cleaners. But only a tiny proportion pose any risk; many more play a positive role.
At present, people facing major surgery are first starved (to prevent choking while under anaesthetic), then fed on intravenous drips after the operation. Bacteria that normally thrive in the gut die off, while the lining of the intestine becomes more permeable as the body increasingly tries to absorb nutrients. This raised permeability can let dangerous pathogens pass into the bloodstream, to cause organ failure or blood-poisoning.
To avoid this, post-operative patients are often given antibiotics. But these indiscriminately kill off both beneficial and harmful bacteria - and leave antibiotic-resistant pathogens unaffected.
Professor Jeppsson said, "The theory is that in ancient times we had to store foods using fermentation products. That let these bacteria into the gut... dogs that bury bones get a constant supply of bacteria from the breakdown of the tissues. Many other animals do the same thing... our food intake now includes too little of these helpful bacteria."
The introduction of the probiotic system is taking a long time, though. The first tests, on six people who were on antibiotics in intensive care and showing signs of organ failure, were carried out in 1996. All made a full recovery.
"It is frustrating, but as soon as we have the full results we could implement this straightaway," said Prof Jeppsson.
A replacement for standard antibiotic use is sorely needed. Earlier this year British doctors were criticised by a House of Commons Select Committee for over-prescribing antibiotics for routine infections - including viruses, against which they have no effect. Meanwhile more hospital patients are falling ill with MRSA, a resistant strain of staphylococcus.
The probiotic approach to surgery has not been tested in Britain, but doctors at Addenbrooke's Hospital in Cambridge are using it as a treatment for irritable bowel syndrome.