Probiotic Prep Doesn't Cut Antibiotic-Linked Diarrhea

A multistrain preparation of lactobacilli and bifidobacteria is not effective for preventing antibiotic-associated diarrhea (AAD) or Clostridium difficile diarrhea (CDD) in older inpatients exposed to antibiotics, according to a study published online in The Lancet.

Stephen J. Allen, MD, from Swansea University in the United Kingdom, and colleagues conducted a multicenter, randomized pragmatic efficacy trial involving inpatients (aged 65 and older) exposed to one or more oral or parenteral antibiotics. Participants were randomized to receive a multistrain preparation of lactobacilli and bifidobacteria for 21 days (1,470 patients) or placebo (1,471 patients).

The researchers found that AAD (including CDD) occurred in 10.8% and 10.4% of participants in the microbial preparation and placebo groups, respectively (relative risk, 1.04; P = 0.71). AAD was infrequently caused by CDD, which occurred in 0.8% and 1.2% of participants, respectively. One or more serious adverse events occurred in 19.7% of participants, with the frequency similar between the two groups and not attributed to trial participation.

"We identified no evidence that a multi-strain preparation of lactobacilli and bifidobacteria was effective in prevention of AAD or CDD," the authors wrote. "An improved understanding of the pathophysiology of AAD is needed to guide future studies."