Mixed microbial preparation offers no protection against AAD
Antibiotic-associated diarrhea (AAD) is a common complication among inpatients aged ≥65 years treated with broad-spectrum antibiotics, which is concerning since Clostridium difficile–induced AAD (CDD) can be life-threatening. A variety of microbial preparations have been tested with the aim of ameliorating or preventing AAD and CDD by restoring the gut microbial flora, but their efficacy remains controversial. Recently, a multicenter efficacy trial found no evidence of any protective effect of a multistrain lactobacilli and bifidobacteria preparation against AAD or CDD.
The double-blind study evaluated 2,981 inpatients aged ≥65 years who were randomized to receive the microbial preparation containing 6×1010 live bacteria (n=1,493) or placebo (n=1,488) once daily for 21 days. All patients had been exposed to one or more antibiotics in the preceding 7 days or were about to begin antibiotic treatment. Follow-up was for 8 weeks.
A modified intention-to-treat analysis of 2,941 participants revealed that AAD (including CDD) occurred in 10.61 percent of patients, and the incidence was similar between the treatment and placebo groups (relative risk [RR] 1.04, 95% CI 0.84-1.28). Moreover, CDD was only observed in 0.99 percent, and again the incidence was similar in both groups (RR 0.71, 95% CI 0.34-1.47). The microbial preparation did not appear to have any protective effect against diarrhea severity, frequency of abdominal symptoms, length of hospital stay or quality of life. The researchers commented that a better understanding of the pathophysiology of AAD is required.
Allen SJ et al. Lactobacilli and bifidobacteria in the prevention of antibiotic-associated diarrhoea and Clostridium difficile diarrhoea in older inpatients (PLACIDE): a randomised, double-blind, placebo-controlled, multicentre trial. Lancet 2013; Aug 7 pii: S0140-6736(13)61218-0. doi: 10.1016/S0140-6736(13)61218-0 [Epub ahead of print]