FRIDAY, Jan. 13, 2017 (HealthDay News) -- A single fecal transplant delivered by enema is apparently no more effective than oral antibiotics in treating recurring cases of a nasty stomach bug, a Canadian study contends.

The study is the first head-to-head comparison between fecal transplant and the current standard of care of antibiotics in treating Clostridium difficile infection, the researchers said.

"We thought it was important to have that comparison so we could know: How much better is it than what we're actually already doing?" said lead author Dr. Susy Hota. She's the medical director of infection prevention and control at University Health Network in Toronto.

In this study, "it looks like they're working about the same," Hota said. "In half the patients, it didn't work, but in the other half, it did."

Infection from C. difficile bacteria can be debilitating, triggering bouts of diarrhea and other intestinal symptoms.

It often occurs in hospitals and nursing homes among people on antibiotics, especially older adults, according to the U.S. Centers for Disease Control and Prevention.

Antibiotics can destroy the gut's good bacteria, allowing the bug to multiply, the researchers said.

Introducing stool from a healthy donor into the bowel of a patient with C. difficile infection is believed to restore the gut's natural mix of microbes (known as microbiota).

Traditionally, doctors prescribe another antibiotic -- oral vancomycin -- to treat C. difficile. But infections treated with antibiotics recur in about 20 percent of patients, the CDC says.

Recent studies suggest fecal transplant may be an effective way to stop the cycle of infection.

Dr. Colleen Kelly, who wasn't involved in the new study, is an assistant professor of medicine at Brown University's Alpert School of Medicine in Providence, R.I.

"The results from this study differ from our clinical experience, in which FMT [fecal microbiota transplantation] is effective for 85 to 90 percent of patients treated," Kelly said.

One reason may be the method of administration -- the Canadian study used a single dose by enema. Delivery by colonoscopy "appears more effective," Kelly said.

Another may be the large volume of stool given in this study.

"I cannot imagine any patient would be able to retain that volume of stool for any length of time," Kelly said.

The study differs from others because the Canadian team was careful to include only patients with documented C. difficile recurrence, "and this is a strength of this study," Kelly noted.

Hota and her colleagues said there's an urgent need for more rigorous research exploring, for example, the optimal dose and delivery, donor selection and timing of treatment.

Their study treated 30 patients with recurrent C. difficile -- 14 got standard treatment and 16 got fecal transplant. However, two dropouts left only 12 in the standard treatment group. Unlike blinded studies, patients and researchers knew which treatment was being administered.

Patients in the fecal transplant group were given a 14-day course of oral vancomycin followed by a single fecal enema. The antibiotic was given to ensure patients' diarrhea was under control before introducing donor stool, Hota said.

The standard treatment group received a 14-day course of oral vancomycin, followed by four weeks of tapering doses of the antibiotic.

Patients were followed for 120 days, since many recurrences of C. difficile occur within three months, Hota explained.

After an interim analysis, researchers stopped the trial because the results showed no real difference in outcomes.

Just over half of the fecal transplant patients and more than 40 percent of the patients on standard treatment experienced a recurrence. In other words, the infection cleared up in about 44 percent of fecal transplant patients and 58 percent of patients on standard care.

"It actually looks like there's really no absolute risk reduction with fecal transplant compared to oral vancomycin," Hota said.

However, fecal transplant has the added benefit of getting patients off antibiotics in a disease driven by antibiotic exposure, she said.

The message is not that fecal transplants are not effective, Hota added. "We need to learn more about doing this properly," and this study contributes to that knowledge, she said.

The findings were published recently in the journal Clinical Infectious Diseases.

More information

The American College of Gastroenterology has more on C. difficile infection.