SWEDEN: Cure against diarrhoea

Researchers at the Karolinska Institute in Stockholm are leading the world in the transplantation of intestinal flora from normal faeces to people suffering diarrhoea, as a result of taking antibiotics for example.

Since the late 1990s, institute researchers have treated more than 100 people with severe diarrhoea in Sweden and Norway where 80% have been cured. The researchers transplanted intestinal flora originally donated by a woman at the time. No side effects have been seen, said Professor Elisabeth Norin in Karolinska's newsmagasine Medisinsk Vetenskap.

Some 1,000 different bacteria are found in the body of a normal person's intestinal flora, with a combined weight of more than one kilogram. The scientists at the Karolinska Institutet were studying the importance of these bacteria for the body's metabolic system, focusing on severe diarrhoea which occurs when something goes wrong with the bacterial balance.

Work has been undertaken at the institute since the 1950s, with unique bacteria-free rats and mice breeding more than 100 generations of animals in a sterile environment. The animals have never developed any bacteria, either in the intestines or anywhere else in their bodies.

By introducing faecal samples in the animals from others with a normal bacteria flora, the flora were quickly established in the experimental animals. But, without a transplanted stool sample, the animals often developed diarrhoea and some died, Norin discovered.

The researchers are now analysing which bacteria are effective in treating diarrhoea in people who have been cured using a technique called 'massive parallel pyrosequencing', developed at the institute by Professor Lars Engstrand four years ago and since then used at laboratories all over the world.

As a byproduct of these analyses, Engstrand has started the analysis of the intestinal contents of the Ice Man Ôtzi found in the Austrian mountains, who died 5,300 years ago. The aim is to try to locate intestinal flora so as to make comparisons over time. One objective is to find out if genes resistant to antibiotics existed before they became used in medicine.

Antibiotics are known to not only kill dangerous bacteria but may also destroy normal flora in the intestines, with the prospect developing diarrhoea that may be difficult to cure.