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 .
Screening of Probiotic Activities of Forty-Seven Strains of Lactobacillus spp. by In Vitro Techniques and Evaluation of the Colonization Ability of Five Selected Strains in Humans
ABSTRACT The probiotic potential of 47 selected strains ofLactobacillus spp . was investigated . The strains were examined for resistance to pH 2.5 and 0.3 % oxgall , adhesion to Caco-2 cells , and antimicrobial activities against enteric pathogenic bacteria in model systems . From the results obtained in vitro , five strains , Lactobacillus rhamnosus 19070 - 2 , L. reuteri DSM 12246 , L. rhamnosus LGG , L. delbrueckii subsp.lactis CHCC 2329 , and L. casei subsp.alactus CHCC 3137 , were selected for in vivo studies . The daily consumption by 12 healthy volunteers of two doses of 1010 freeze-dried bacteria of the selected strains for 18 days was followed by a washout period of 17 days . Fecal sample s were taken at days 0 and 18 and during the washout period at days 5 and 11.Lactobacillus isolates were initially identified by API 50CHL and internal transcribed spacer PCR , and their identities were confirmed by restriction enzyme analysis in combination with pulsed-field gel electrophoresis . Among the tested strains , L. rhamnosus 19070 - 2 , L. reuteri DSM 12246 , and L. rhamnosus LGG were identified most frequently in fecal sample s ; they were found in 10 , 8 , and 7 of the 12 sample s tested during the intervention period , respectively , whereas reisolations were less frequent in the washout period . The bacteria were reisolated in concentrations from 105 to 108 cells/g of feces . Survival and reisolation of the bacteria in vivo appeared to be linked to pH tolerance , adhesion , and antimicrobial properties in vitro
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 .