Clostridium difficile bacteria are a leading cause of infectious diarrhoea that generally affects patients who have recently undergone antibiotic treatment or who are hospitalized. Although microbial signatures could potentially be used for identifying subsets of patients that may benefit early from conventional therapies for C. difficile infection when it occurs, the role of gut microbiota manipulation through probiotics in reducing the incidence of C. difficile-associated diarrhoea (CDAD) in elderly hospitalized patients is still unsettled.

A recent systematic review, led by Dr. Michelle DeCoux Hampton from the School of Nursing at Samuel Merritt University and UCSF Joana Briggs Institute Centre for Synthesis & Implementation, has found that probiotics’ effect is not better than placebo for reducing the incidence of Clostridium difficile-associated diarrhoea in elderly hospitalized patients.

The review included only randomized controlled trials -published in English between 1978, when the first case of CDAD was reported, and 2015- that evaluated the effectiveness of probiotics of varying strains, doses, and frequencies for prevention of CDAD in elderly hospitalized patients compared to a placebo. Incidence or relapse of CDAD was the primary outcome, which was defined by the presence of diarrhoea and verified by positive results for stool enzyme immunoassay for enterotoxin A and cytotoxin B produced by C. difficile bacteria.

The sample of participants assessed were aged 60 years and older who were residents of acute- and post-acute care facilities, undergoing or planning to undergo antibiotic treatment for the treatment of any infectious condition; those already undergoing treatment for CDAD were excluded.

From an initial 778 studies, 5 randomized controlled trials (including 3,461 participants) met the inclusion criteria for the systematic review and were finally included in the review. One study demonstrated a statistically significant difference in CDAD incidence between the probiotic and placebo groups, but it showed a small effect size with little impact on the overall meta-analysis.

In conclusion, this meta-analysis shows that probiotics’ effect is not better in the reduction of CDAD incidence in elderly hospitalized patients than placebo. Due to the heterogeneity in methodologies of the analysed studies (type of probiotic bacteria, number of strains used, method of administration-capsules or food products, duration of probiotic administration, and dose), further research is needed to investigate the effectiveness of probiotics for CDAD prevention in this population.

A related systematic review and meta-analysis by Shen, et al. on probiotics for preventing Clostridium difficile infection in a broader population (hospitalized adults taking antibiotics) came to a different conclusion — that timely probiotic administration may reduce risk of C. difficile infection by more than 50%. Watch for upcoming GMFH coverage of this new publication.



Vernaya M, McAdam J, Hampton MD. Effectiveness of probiotics in reducing the incidence of Clostridium difficile-associated diarrhea in elderly patients: a systematic review. JBI Database System Rev Implement Rep. 2017; 15(1):140-64. doi: 10.11124/JBISRIR-2016-003234.