Conclusion : Based on the available data and taking into account the safety profile of RCTs , probiotic consumption appears to be a feasible way to decrease the incidence of RTIs in children
Background : Respiratory tract infections ( RTIs ) represent one of the main health problems in children .
Probiotics are viable bacteria that colonize the intestine and affect the host intestinal microbial balance .
Accumulating evidence suggests that probiotic consumption may decrease the incidence of or modify RTIs .
The authors systematic ally review ed data from r and omized controlled trials ( RCTs ) to investigate the effect of probiotic consumption on  RTIs in children .
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 st and ard 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 r and omized , double-blind , placebo-controlled trial in 727 hospitalized children ( aged 1 - 18 y ) . The children were r and omly 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 clinical trials.gov as NCT01702766
Conclusion : Based on the available data and taking into account the safety profile of RCTs , probiotic consumption appears to be a feasible way to decrease the incidence of RTIs in children
Background : Respiratory tract infections ( RTIs ) represent one of the main health problems in children .
Probiotics are viable bacteria that colonize the intestine and affect the host intestinal microbial balance .
Accumulating evidence suggests that probiotic consumption may decrease the incidence of or modify RTIs .
The authors systematic ally review ed data from r and omized controlled trials ( RCTs ) to investigate the effect of probiotic consumption on  RTIs in children .