Randomised placebo-controlled double blind multicentric trial on efficacy and safety of Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 for prevention of antibiotic-associated diarrhoea.

Aims: To evaluate the effectiveness, safety and tolerability of a probiotic formulation containing Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 in the prevention of antibiotic associated diarrhoea (AAD).
Methods and Material: A double-blind randomised placebo controlled multicentric trial was conducted in adults who were prescribed a seven-day course of oral antibiotic (either cefadroxil or amoxycillin) for a documented indication. The effectiveness of a 14-day therapy (concomitant with antibiotic course and seven days thereafter) of the probiotic formulation in preventing AAD was evaluated. Safety profile was assessed by monitoring of all treatment emergent adverse events and tolerability on a global well being scale.
Results: The incidence of AAD in the probiotic group was 10.8% compared to 15.6% in the placebo group, the difference being statistically non-significant (p = 0.19). The relative risk for AAD was 0.7 with the 95% CI being 0.4 to 1.2. The diarrhoea duration in the probiotic group was two days with an interquartile range of 1- 3 days and was significantly less (p = 0.01) than the placebo group which was four days with an interquartile range of 3 - 5.5 days. Subgroup analysis of subjects with AAD showed that the incidence of severe diarrhoea (watery stools) was 96% in the placebo group (25 out of 26) compared to 31.6% (6 out of 19) in the probiotic group and this difference was significant statistically (p < 0.001). Four mild, non-serious, adverse events were detected (2.0%) in the probiotic group but there were none in the placebo group.
Conclusion: This randomised controlled trial shows that prophylactic administration of the probiotic formulation containing Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12, did not effectively lower the incidence of AAD in adults. However, compared to placebo the duration of diarrhoea in the probiotic group was significantly reduced. Its tolerability and safety profile were good.