Few treatments exist for people infected with the nasty gut superbug C.difficile, although new approaches based on transplanting fecal matter taken from stools of healthy people are proving successful. Now a new study claims poop made artificially in the lab not only cures the infection more effectively, but is safer, more stable and adaptable, and overcomes the “yuck” factor that puts patients, and some medical professionals, off this type of treatment.
The synthetic stool, called RePOOPulate, is the creation of Emma Allen-Vercoe, a microbiologist at the University of Guelph in Canada.
Allen-Vercoe is also the senior author of a paper describing a study of the artificial “super-probiotic” poop that was published in the first issue of a new online, peer-reviewed science journal Microbiome on Wednesday.
C. difficile is a bacterium that causes gastrointestinal problems, including severe diarrhea. It has acquired superbug status because many strains have now developed resistance to first line drugs, and its spores, through which it spreads, stubbornly resist many antibacterial products used to clean surfaces.
As a consequence, the bacterium overpopulates the gut, producing nasty toxins, when healthy, less resistant, gut bacteria are killed off by antibiotics.
Outbreaks resulting from recurring infections of C. difficile tend to occur where lots of people who are either sick or vulnerable to illness are under one roof, such as in hospitals and residential care homes.
Treatments using stool transplants to treat C.difficile were recently developed as an alternative to drug-based therapies after studies showed patients recovered quickly with apparently no ill side effects.
For example, one study, reported at a conference in the US in October 2012, showed how treating patients with donated human stool mixed with water through a nasogastric tube or colonoscopy resulted in a complete and fast recovery with no negative side effects in 43 out of 49 of them.
But Allen-Vercoe says in a press statement, while stool transplants using fecal matter from healthy people is an effective therapy for recurring C. difficile infections, they carry the risk of introducing other unknown pathogens, which potentially “puts people at risk for future disease”.
Stool transplant therapy is also limited by lack of standardized treatment regimens.
Then there is also the difficulty that many patients, and some health professionals too, are put off by the idea of squirting donated “poop” through a nasal or colonoscopy tube.
Allen-Vercoe, who is a professor in Guelph’s Department of Molecular and Cellular Biology, made her synthetic poop from purified intestinal bacteria grown in a piece of lab equipment that she and her team nicknamed the “Robo-gut”.
Robo-gut essentially mimics the environment of the gut so as to produce a “super-probiotic” mix of the friendly bacteria that exist in the large intestine of healthy humans.
For their proof of principle study, the researchers tested the synthetic stool on two patients with chronic C. difficile infections that were failing to respond to several rounds of antibiotics.
Both patients were free of symptoms within three days of treatment, and both still tested negative for C. difficile six months later.
During the follow up, the researchers also tested the microbial profiles of the gut enviroment of both patients. These showed that some of the features of the probiotic synthetic stool had persisted and stabilized in their intestines.
“This is important because most commercially available probiotics only colonize transiently,” says Allen-Vercoe.
The team says their new synthetic stool is not only more effective, but also safer, more stable and adaptable than using donated human fecal matter to wipe out C. difficile.
The method can be tailored to individual patient needs, it is easily reproduced, and is more appealing to many patients and physicians, says Allen-Vercoe.
It is also safer, she adds, because since “the exact composition of the bacteria administered is known and can be controlled”, it eliminates the risk of transmitting an infectious disease.
“It’s an exciting finding,” she says.
Allen-Vercoe hopes her synthetic poop idea can also be used to treat other gastrointestinal problems, such as inflammatory bowel disease, obesity and even autism by replacing abnormal gut microbial ecosystems with healthier versions.
Written by Catharine Paddock PhD