title: Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis.
abstract: BACKGROUND
  Probiotics are live microorganisms intended to confer a health benefit when consumed. One condition for which probiotics have been advocated is the diarrhea that is a common adverse effect of antibiotic use.
  
  
  OBJECTIVE
  To evaluate the evidence for probiotic use in the prevention and treatment of antibiotic-associated diarrhea (AAD).
  
  
  METHODS
  Twelve electronic databases were searched (DARE, Cochrane Library of Systematic Reviews, CENTRAL, PubMed, EMBASE, CINAHL, AMED, MANTIS, TOXLINE, ToxFILE, NTIS, and AGRICOLA) and references of included studies and reviews were screened from database inception to February 2012, without language restriction.
  
  
  METHODS
  Two independent reviewers identified parallel randomized controlled trials (RCTs) of probiotics (Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, and/or Bacillus) for the prevention or treatment of AAD.
  
  
  METHODS
  Two independent reviewers extracted the data and assessed trial quality.
  
  
  RESULTS
  A total of 82 RCTs met inclusion criteria. The majority used Lactobacillus-based interventions alone or in combination with other genera; strains were poorly documented. The pooled relative risk in a DerSimonian-Laird random-effects meta-analysis of 63 RCTs, which included 11 811 participants, indicated a statistically significant association of probiotic administration with reduction in AAD (relative risk, 0.58; 95% CI, 0.50 to 0.68; P < .001; I(2), 54%; [risk difference, -0.07; 95% CI, -0.10 to -0.05], [number needed to treat, 13; 95% CI, 10.3 to 19.1]) in trials reporting on the number of patients with AAD. This result was relatively insensitive to numerous subgroup analyses. However, there exists significant heterogeneity in pooled results and the evidence is insufficient to determine whether this association varies systematically by population, antibiotic characteristic, or probiotic preparation.
  
  
  CONCLUSIONS
  The pooled evidence suggests that probiotics are associated with a reduction in AAD. More research is needed to determine which probiotics are associated with the greatest efficacy and for which patients receiving which specific antibiotics.
authors.affiliation: Southern California Evidence-Based Practice Center, RAND Health, 1776 Main St, Santa Monica, CA 90401, USA. susanne_hempel@rand.org
authors.forename: Susanne
authors.initials: S
authors.lastname: Hempel
authors.forename: Sydne J
authors.initials: SJ
authors.lastname: Newberry
authors.forename: Alicia R
authors.initials: AR
authors.lastname: Maher
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Jeremy N V
authors.initials: JN
authors.lastname: Miles
authors.forename: Roberta
authors.initials: R
authors.lastname: Shanman
authors.forename: Breanne
authors.initials: B
authors.lastname: Johnsen
authors.forename: Paul G
authors.initials: PG
authors.lastname: Shekelle
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000627:therapeutic use; D003967:Diarrhea / Q000139:chemically induced* / Q000517:prevention & control*; D006801:Humans; D019936:Probiotics / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic
chemical_list: D000900:Anti-Bacterial Agents