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Importance: Probiotics are frequently used by residents in care homes (residential homes or nursing homes that provide residents with 24-hour support for personal care or nursing care), although the evidence on whether probiotics prevent infections and reduce antibiotic use in these settings is limited. Objective: To determine whether a daily oral probiotic combination of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis BB-12 compared with placebo reduces antibiotic administration in care home residents. Design, Setting, and Participants: Placebo-controlled randomized clinical trial of 310 care home residents, aged 65 years and older, recruited from 23 care homes in the United Kingdom between December 2016 and May 2018, with last follow-up on October 31, 2018. Interventions: Study participants were randomized to receive a daily capsule containing a probiotic combination of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis BB-12 (total cell count per capsule, 1.3 × 1010 to 1.6 × 1010) (n = 155), or daily matched placebo (n = 155), for up to 1 year. Main Outcomes and Measures: The primary outcome was cumulative antibiotic administration days for all-cause infections measured from randomization for up to 1 year. Results: Among 310 randomized care home residents (mean age, 85.3 years; 66.8% women), 195 (62.9%) remained alive and completed the trial. Participant diary data (daily data including study product use, antibiotic administration, and signs of infection) were available for 98.7% randomized to the probiotic group and 97.4% randomized to placebo. Care home residents randomized to the probiotic group had a mean of 12.9 cumulative systemic antibiotic administration days (95% CI, 0 to 18.05), and residents randomized to placebo had a mean of 12.0 days (95% CI, 0 to 16.95) (absolute difference, 0.9 days [95% CI, -3.25 to 5.05]; adjusted incidence rate ratio, 1.13 [95% CI, 0.79 to 1.63]; P = .50). A total of 120 care home residents experienced 283 adverse events (150 adverse events in the probiotic group and 133 in the placebo group). Hospitalizations accounted for 94 of the events in probiotic group and 78 events in the placebo group, and deaths accounted for 33 of the events in the probiotic group and 32 of the events in the placebo group. Conclusions and Relevance: Among care home residents in the United Kingdom, a daily dose of a probiotic combination of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis BB-12 did not significantly reduce antibiotic administration for all-cause infections. These findings do not support the use of probiotics in this setting. Trial Registration: ISRCTN Identifier:16392920.

Original publication




Journal article



Publication Date





47 - 56


Aged, Aged, 80 and over, Anti-Bacterial Agents, Assisted Living Facilities, Bacterial Infections, Bifidobacterium animalis, Double-Blind Method, Drug Utilization, Feces, Female, Humans, Lactobacillus rhamnosus, Male, Nursing Homes, Probiotics, United Kingdom