Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies

Department Chair

John Cavenagh, MBA, PhD, PA-C


OBJECTIVE: The objective of this selective Evidence Based Medicine (EBM) review is to determine if the use of probiotics can prevent the incidence of antibiotic-associated diarrhea (AAD) in adults using one or more antibiotics.

STUDY DESIGN: Systematic review of three randomized, double-blind, placebo controlled trials in the English language published between 2013 and 2014.

DATA SOURCES: Data sources obtained for this review were articles published in peerreviewed journals found using PubMed and Cochrane databases.

OUTCOME MEASURED: All three studies defined diarrhea as the passage of three or more loose stools in a 24-hour period. All the studies used the Bristol Stool Scale. Stool consistency and frequency was recorded by patients, relatives, or clinical staff.

RESULTS: Three double-blind, placebo-controlled trials were included and analyzed in this review. None of the three studies showed a statistical significance in AAD between their control groups and the groups receiving probiotics. The Chatterjee et al. study had a p-value of 0.19 and a Numbers Needed to Treat (NNT) of -20.83, the Wright et al. study had a p-value of 0.729 and a NNT of 28.57, and the Allen et al. study had a p-value of 0.72 and a NNT of 250.

CONCLUSION: The three double-blind, placebo-controlled trials analyzed in this review showed no benefit in the use of probiotics for the prevention of AAD when comparing the placebo groups and the probiotics groups.