The development of nosocomial diarrhea, especially rotavirus infection, in children can significantly increase the length of hospital stay and increase the cost of treatment. In previous studies on the prevention of nosocomial diarrhea, various probiotic preparations have been studied and the results have been mixed. There is evidence of a successful use of L. rhamnosus GG (LGG) to prevent the development of nosocomial diarrhea, in addition, promising results have been obtained with Bifidobacterium bifidum (formerly called B. lactis) and Streptococcus thermophilus. However, in a number of studies, the effectiveness of probiotics for the prevention of nosocomial diarrhea has not been proven. It should be noted that not all probiotics are created equal, and the effectiveness of each probiotic should be assessed separately.

To date, there are two completed studies in which moderate efficacy of L. has been demonstrated. reuteri ATCC55730 as an additional component of rehydration therapy in the treatment of acute infectious diarrhea of rotavirus origin in children. It seems that L. reuteri ATCC55730 is a carrier of resistance factors on mobile genetic elements to tetracycline and lincomycin, initiated the replacement of the use of the mother strain by a daughter strain (L. reuteri DSM 17938) which has no plasmid resistance factors.

The objective of the study carried out in Poland was to evaluate the effectiveness of the administration of Lactobacillus reuteri DSM 17938 in order to prevent the development of nosocomial diarrhea. The choice of the probiotic strain studied was made taking into account its wide prevalence in many countries, including Poland.

This randomized, double-blind, placebo-controlled study included children aged 1 to 48 months (n = 106) who were hospitalized for hospital treatment, regardless of the nature of the disease, with the exception of diarrhea. Study participants were assigned L. reuteri DSM 17938 at a dose of 108 CFU (n = 54) or a placebo (n = 52) oral once a day for the duration of treatment in a hospital environment. The diagnosis of nosocomial diarrhea was valid if there were 3 episodes of frequent loose or watery stools within 24 hours of hospital admission (risk ratio 1.06, 95% CI 0.7-1.5 ).

Data on all study participants were included in the final analysis. It turned out that using L. reuteri DSM 17938 did not significantly affect the risk of nosocomial diarrhea. Of the 54 children in the main group, 18 developed diarrhea, and of the 52 children in the placebo group, 16 (33% vs 31%). Rotavirus infection was diagnosed in 19 children with no significant differences between the groups. In addition, there was no significant difference in the other secondary endpoints between the study groups (incidence of rotavirus infection, incidence and duration of diarrhea, recurrence of diarrhea, number of cases chronic diarrhea, length of hospital stay and proportion of patients requiring rehydration therapy) No adverse events were noted in either group.

Researchers explain the lack of effect by a number of factors, mainly related to the probiotic itself. First of all, the wrong choice of a probiotic strain in a certain clinical situation can lead to an insufficient effect. Documented efficacy of L. reuteri DSM 17938 in one case, for example for the treatment of spastic intestinal colic in children aged 1 year, does not guarantee efficacy in another situation. Second, an inadequate dose of a probiotic can also be a cause of treatment failure. The children received L. reuteri DSM 17938 probiotics at the manufacturer's recommended dose, although for different probiotics the optimal dose has not yet been clearly established. It cannot be excluded that a higher dose of probiotics may be necessary to prevent diseases with diarrhea syndrome.

Thus, in children treated in hospital, the appointment of L. reuteri DSM 17938 had no significant effect on the incidence of diarrhea, in particular due to rotavirus infection.

The choice of probiotic drug and the optimal dose can significantly affect the effectiveness of treatment. Additional evidence is required to prove this judgment.