After cultivating and scrutinising the genetic makeup of 137 bacteria from the human intestine, the scientists have a better understanding of how our bacterial "microbiome" helps keep us healthy.

This is important because imbalances in our gut microbiome may contribute to complex conditions and disorders including obesity, irritable bowel syndrome and certain allergies.

The research, published on Thursday in the journal Nature, will allow scientists to create tailor-made treatments with specific beneficial bacteria.

"We expect our research might lead to important new therapies to replace the use of antibiotics and faecal transplants to treat some gut infections," said collaborator Samuel Forster from Melbourne's Centre for Innate Immunity and Infectious Diseases at the Hudson Institute of Medical Research.

Working at the Wellcome Trust Sanger Institute in Britain, the researchers developed a process to grow the majority of the bacteria from the human gut, which accounts for roughly 2 per cent of a person's body weight.

"Many of these bacteria are sensitive to oxygen and are difficult to culture in the laboratory," Dr Forster explained. "So, until now, it has been extremely difficult to isolate and study them."

The "massive bacterial discovery", as Dr Forster calls it, is "like a treasure chest of potential therapeutic tools: until now we have known the chest existed but were simply unable to open it".

The research also revealed that approximately one-third of species residing within our gut are able to form spores. "These spores are like bacterial seeds which are highly resistant and designed to survive for long periods when exposed to oxygen, heat and the environment," Dr Forster said.

The "normal" health associated bacteria may also rely on spores for transmission. "This potentially sheds light on the causes of many gut conditions," he said.

He said the work now provided scientists with hundreds of individual candidates, and many millions of combinations, that may be useful in treating gastrointestinal conditions.

"With the new techniques we have developed, and the appropriate facilities, the only limitation is how many bacterial colonies we need to pick in order to get the ones we are searching for," Dr Forster said.

Rationally selected treatments, based on bacterio-therapy, will enter clinical trials within the next few years, he said. "But widespread clinical use will take longer."

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