New cases of C. difficile-associated diarrhea among hospitalized patients taking antibiotics can be reduced by two-thirds with the use of probiotics, according to new research published Monday in the Annals of Internal Medicine.

“Probiotics are not a magic bullet, but these results suggest therapeutic probiotic agents, as well as some yogurts and probiotic dairy products, may be vastly under-used in some nursing homes and hospitals,” says lead author Dr. Bradley Johnston, assistant professor in the Department of Clinical Epidemiology and Biostatistics, and a scientist and clinical epidemiologist at SickKids Hospital in Toronto.

Johnston led a research team which compiled findings from 3,818 patients in 20 randomized-controlled trials. The trials tracked rates of probiotic use among in-patients and out-patients on antibiotics, and analyzed the rates of diarrheal illness associated with C. difficile. Probiotic powder and capsules, as well as yogurt, were included in the studies analyzed.

“That’s why probiotics could be an effective, safe and relatively inexpensive approach to prevent C. difficile-associated diarrheal illness,” says Johnston.

“The burden that this illness places on the healthcare system and the impact it has on patients’ morbidity and mortality are substantial. Our findings demonstrate that probiotics have the potential to save lives and improve the quality of life of hospitalized patients at risk of contracting C. difficile associated diarrhea,” says Dr. Stephanie Ma, co-author and chief resident in Plastic and Reconstructive Surgery at McMaster.

No serious adverse side-effects were associated with the use of probiotics. Projected onto current rates, probiotic prophylaxis would prevent three episodes of C. difficile-associated diarrhea per 100 patients (or 33 fewer episodes per thousand).

“Because C. difficile forms spores, it is difficult to eradicate from the environment. Probiotics can be easily integrated into the diets of hospitalized patients,” says co-author Dr. Mark Loeb, professor of Pathology and Molecular Medicine in the Michael G. DeGroote School of Medicine, and division director of Infectious Diseases.

While treating and preventing infections, antibiotics can also destroy healthy bacteria in the colon. Probiotics help to reintroduce healthy bacteria.

Older hospitalized adults who are exposed to antibiotics are most at risk of serious C. difficile infection. It accounts for up to half of all diarrheal illness in hospital, and is a significant cause of illness and death in hospitalized adults.