Scientists at Aberdeen University are hoping a cocktail of naturally occurring bacteria could prove a potent new weapon against the hospital bug Clostridium difficile.
Research has identified six organisms that suppressed a highly contagious strain of C. diff in mice, three of which have not been described before.
The strain studied, known as O27, has been responsible for epidemics in Europe, North America and Australia.
It is hoped the discovery could lead to new ways of treating and preventing C. diff infection without resorting to antibiotics, which become less effective the more they are used.
C. diff can cause bloating diarrhoea, and abdominal pain, and contributed to more than 2,000 deaths in the UK last year.
The bug has a long contagious "supershedding" period that is very difficult to treat with antibiotics. During this time, the bug sheds highly resistant spores that contaminate the environment.
It lives naturally in the bodies of some people where other gut bacteria hold back its numbers and stop it spreading. Some antibiotics can destroy these "friendly" bacteria, allowing the gut to be overrun by C. diff.
Professor Harry Flint, a leading member of the team from the University of Aberdeen, said: "The mixture of six bacterial species effectively and reproducibly suppressed the C. difficile supershedder state in mice, restoring the healthy bacterial diversity of the gut."
The results are published in the online journal Public Library of Science Pathogens.
Co-author Professor Gordon Dougan, from the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, said: "Our results open the way to reduce the over-use of antibiotic treatment and harness the potential of naturally occurring microbial communities to treat C. difficile infection and transmission, and potentially other diseases associated with microbial imbalances.
"Faecal transplantation is viewed as an alternative treatment but it is not widely used because of the risk of introducing harmful pathogens as well as general patient aversion.
"This model encapsulates some of the features of faecal therapy and acts as a basis to develop standardised treatment mixture."