RESUMO
We compared fecal samples from responders and non-responders to administration of Lactobacillus reuteri DSM 17938. Data for this post hoc analysis were collected from an RCT assessing the efficacy of L. reuteri for the management of acute gastroenteritis. Responders were defined as subjects with diarrhea lasting no longer than 48 h. 44 children (17 responders and 27 non-responders) were analyzed. There were no differences in clinical characteristics and gut colonization between both groups. In the responder group, there were significantly lower levels of five metabolites before beginning of the intervention: lactate, choline, ethanol, creatine, and formate. The fecal calprotectin level did not differ between groups prior to the intervention, but its level was significantly lower after intervention in the responder group. Possibly, the responder group with a "metabolic niche", including lower level of metabolites, especially lactate, that are potential products of Lactobacillus genus, would determine the response to probiotic treatment. These findings need to be confirmed, but identification of some differences in the fecal metabolomics and the calprotectin level suggests that further studies are warranted.