Evidence Insufficient to Show That Probiotics Prevent CDI

There is insufficient evidence that probiotics prevent Clostridioides difficile infection (CDI) in older hospitalized patients taking antibiotics, according to a study published in Frontiers in Medicine.

The researchers noted that CDI is most prevalent in older patients receiving broad-spectrum antibiotics, nursing home residents, and hospitalized older patients. They explained that intestinal microbiota disruption, particularly in older adults, is a significant risk factor for CDI, as the microbiota protect against pathogenic bacteria.

A patient’s intestinal microbiota balance could be disturbed by various factors, including antibiotic therapy exposure and the natural aging process. Despite this, the current standard therapeutic measure is antibiotic therapy, which the researchers noted increases the recurrence risk of infection.

Because of this, probiotics are emerging as a potential alternative preventive and therapeutic strategy for managing gastrointestinal conditions like diarrhea. Some past studies found positive effects of probiotics on patients with CDI, while others found that probiotics were ineffective.

Consequently, the researchers conducted a review to find a more definitive consensus on whether probiotics prevent CDI by reviewing more recent studies. The researchers conducted their search between September 2021 and January 2022, limiting their search to English studies published between 2011 and 2021 across databases PubMed, the Web of Science, and Scopus using specific keyword combinations.

They included studies with clinical and cohort trials that addressed the effect of probiotic microorganism intervention in preventing CDI in older adults using a concurrent or retrospective control group that received no treatment or only a placebo; studies with outcomes like watery stools, stool consistency, self-reported diarrhea, and physician-defined diarrhea were also included in this analysis. On the other hand, the researchers excluded articles not available in full, dissertations, review articles, letters, opinions, commentaries, and reviews.

The researchers categorized data from the studies analyzed based on their respective publications, research objectives, study types, and levels of evidence. They also recorded study population demographics, sample sizes, outcome variables, probiotics used, and the dose administered. The researchers narrowed their population by grading each article “according to its level of evidence and assessed for study quality in the domains of sample selection, analysis of exposures and outcomes, and data analysis.”

Digestive system | Image credit: sdecoret - stock.adobe.com

Through their literature search, the researchers found 7 eligible studies, 3 of which were conducted in the United States, 2 in the United Kingdom, 1 in Denmark, and 1 in Japan. Each study’s population consisted of hospitalized patients. The mean age of the probiotic group was 74.8 years and the mean age of the placebo group was 74.6 years (P = .693).

Three studies demonstrated that older patients using probiotics could decrease CDI. The studies evaluated a variety of probiotic strains, but Saccharomyces boulardii was found to be most beneficial as it “can produce a protease that inactivates the receptor site for C difficile toxin A, conferring biological plausibility to its use in CDI.” Despite this, the researchers did not find consensus among all studies analyzed that probiotic use could decrease CDI.

The researchers noted several limitations to their study, including possible selection biases. They mostly reviewed retrospective cohort studies, meaning the results of the included clinical trials may not apply to the general population due to their strict eligibility criteria.

Because of the study’s limitations and insufficient findings, the researchers explained that more evidence is needed to prove that probiotics prevent CDI in older, hospitalized patients taking antibiotics. In terms of future research, they concluded that “robust clinical studies that include the S boulardii strain are needed to address the scientific and clinical gaps on the potential protective effect of probiotics on CDI.”

Reference

Barbosa MLL, Albano MO, Martins CDS, Warren CA, Brito GAC. Role of probiotics in preventing Clostridioides difficile infection in older adults: an integrative review. Front Med (Lausanne). 2023;10:1219225. doi:10.3389/fmed.2023.1219225