Bifidobacterium animalis subsp. lactis fails to prevent common infections in hospitalized children: a randomized, double-blind, placebo-controlled study.

Background: The incidence of nosocomial infections in children in developed countries is still high, ranging from 8% to 30%, and standard preventive measures, such as increased hygiene, are not sufficiently efficacious. One of the potential strategies for their prevention is the use of probiotics.

Objective: The aim of the study was to investigate the role of Bifidobacterium animalis subsp. lactis in preventing nosocomial infections in the acute hospital setting.

Design: We conducted a randomized, double-blind, placebo-controlled trial in 727 hospitalized children (aged 1-18 y). The children were randomly allocated to receive placebo (placebo group, n = 365) or B. animalis subsp. lactis at a dose of 10(9) colony-forming units/d (intervention group, n = 362) once daily for the entire duration of the hospital stay. Nosocomial infections were defined as infections that occurred >48 h after hospital admission and that were not present or incubating at the time of admission.

Results: Analysis was performed on an intention-to-treat basis. There was no difference in the study primary outcome or incidence of common nosocomial gastrointestinal and respiratory tract infections between groups (22 vs. 29 infections, respectively; incidence rate ratio = 0.76; 95% CI: 0.41, 1.36; P = 0.32). No difference was found for the duration of common nosocomial infections [mean (range): 3.58 (1-7) vs. 3.79 (1-8) d, in placebo vs. intervention group; P = 0.74]. There was also no difference between the intervention and placebo groups for any of the other secondary outcomes (incidence of gastrointestinal and respiratory tract infections separately, duration of gastrointestinal and respiratory infections, and duration of hospitalization) and exploratory outcomes (gastrointestinal and respiratory symptoms, severity of gastrointestinal and respiratory tract infections, and the use of antibiotics).

Conclusions: The results of this study show that the use of B. animalis subsp. lactis failed to prevent nosocomial infections in an acute-setting pediatric hospital in children who were >1 y of age. However, it should be taken into account that the overall incidence of nosocomial infections was lower than expected. This trial was registered at clinicaltrials.gov as NCT01702766.