Do probiotics decrease antibiotic-associated diarrhea?

Journal of Family Practice, April, 2003 by John R. McConaghy

Cremonini F, Di Caro S, Nista EC, et al. Meta-analysis: the effect of probiotic administration on antibiotic-associated diarrhoea. Aliment Pharmacol Ther 2002; 16:1461-1467.

* PRACTICE RECOMMENDATIONS

Taking probiotics containing Lactobacillus or Saccharomyces species decreases the incidence of antibiotic-induced diarrhea from 23% to 13% (number needed to treat=10). The optimal dose of ingested organisms is unknown.

* BACKGROUND

Probiotics are living microorganisms that, when ingested, colonize the intestine. Altering the intestinal flora with Lactobacillus and Saccharomyces species is thought to prevent traveler's and antibiotic-associated diarrhea.

* POPULATION STUDIED

The authors of this meta-analysis conducted a comprehensive search of MEDLINE, Cochrane database, abstracts of gastroenterology meetings, and also sought unpublished data. They identified 41 studies, 7 (n=881) of which were randomized, placebo-controlled trials, with a minimum follow-up of 2 weeks. Four of the 7 studies evaluated Lactobacillus spp and 3 included Saccharomyces boulardii (doses not specified). In all studies, the outcome for diarrhea was simply present or not present. Two studies examined infants and children; the rest examined adults, and 1 of these focused on the elderly. Patients had taken [beta]-Lactam or other oral antibiotics.

* STUDY DESIGN AND VALIDITY

Two of the authors independently evaluated the quality of the trials according to standard criteria. The results of this analysis were not reported, so details of excluded trials are not known. The study did not describe how the data were extracted by the authors.

Included studies were homogeneous, and a funnel scatterplot demonstrated no study publication bias.

* OUTCOMES MEASURED

The only outcome of this analysis was the presence or absence of diarrhea during antibiotic treatment.

* RESULTS

Diarrhea occurred during antibiotic therapy in 20% of patients. (1) This likelihood was decreased to 8% in patients taking any probiotic (relative risk=0.4; 95% confidence interval [CI]=0.28-0.57).

After this study was published, the Bandolier Library analyzed and presented the data from the same 7 studies and added the results from 2 more studies. In their analysis, the incidence of antibiotic-associated diarrhea decreased from 23% to 13% in patients given probiotics (number needed to treat=10; 95% CI=7.1-17). Results were similar in patients receiving Lactobacillus or Saccharomyces.

No information was given about side effects or standardization of probiotic doses. The usual caveat regarding these unregulated products was given--ie, the products available for sale may not represent the same formulations used in the study. One recommendation stated that several billion organisms should be taken to obtain gut colonization.

REFERENCE

(1.) Probiotics for antibiotic-associated diarrhoea. Oxford: Bandolier Library, Oxford University. Available at: http://www.jr2.ox.ac.uk/bandolier/band104/b104-2.html. Accessed on December 16 2002.

John R. McConaghy, MD, Director, Family Practice Residency, Department of Family Medicine, Ohio State University, Columbus. E-mail: mcconaghy-1@medctr.osu.edu.