NEW YORK (Reuters Health) – Giving the probiotic Lactobacillus reuteri DSM 17938 to hospitalized children is unlikely to protect them from nosocomial diarrhea, including rotavirus infection, according to a study conducted in Poland.
“In children, healthcare-associated diarrhea, in particular due to rotavirus, may prolong the hospital stay and increase medical costs, prompting interest in effective, low-cost, preventive strategies,” Dr. Hania Szajewska, of the Department of Pediatrics, The Medical University of Warsaw, who worked on the study, told Reuters Health by email.
A few studies have examined the preventive effect of different probiotics on nosocomial diarrhea, with mixed results. There is some evidence to support the use of Lactobacillus rhamnosus GG (LGG) for this purpose, as well as some promising evidence for use of Bifidobacterium bifidum (recently renamed B lactis) and Streptococcus thermophilus to prevent nosocomial diarrhea. Some studies have found no preventive effects of probiotics.
But “not all probiotics are equal; the efficacy and safety of each probiotic strain has to be evaluated separately,” Dr. Szajewska noted.
“Our study was designed to evaluate the role of L reuteri DSM 17938 administration compared with placebo for preventing the development of nosocomial diarrhea in a pediatric hospital setting. The choice of the probiotic strain was determined by the fact that it is widely available in many countries, including Poland where the study was conducted,” Dr. Szajewska said.
In a report online February 10 in The Journal of Pediatrics, Dr. Szajewska and co-author Dr. Monika Wanke say there is a rationale for expecting a protective effect of this specific probiotic based on the results of two trials with a mother strain, L reuteri ATCC 55730 (also known as SD2112). “These studies provided evidence of a moderate beneficial effect of L reuteri ATCC 55730 as an adjunct to rehydration therapy in the treatment of acute infectious diarrhea of rotaviral origin in children,” they report.
However, because L reuteri ATCC 55730 was found to carry potentially transferable resistance traits for tetracycline and lincomycin, it has been replaced by the daughter strain (L reuteri DSM 17938), “with no plasmid-borne resistances.”
The current study involved 106 children, 1 to 48 months old, admitted to the hospital for reasons other than diarrhea. For the duration of their hospital stay, they received either 10^8 colony-forming units of L reuteri DSM 17938 or placebo by mouth once daily.
According to the researchers, L reuteri DSM 17938 did not significantly affect the risk of developing nosocomial diarrhea, defined as three loose or watery stools per day in a 24-hour period that occurred more than 72 hours after admission (risk ratio 1.06) or rotavirus infection (risk ratio 1.04). Of the 54 children in the probiotic group, 18 (33%) developed diarrhea compared with 16 of the 52 children (31%) in the placebo group. Rotavirus was detected in 19 children, with no significant difference between the study groups.
There was also no between-group difference for any of a number of secondary outcomes including duration of diarrhea, incidence of recurrent or chronic diarrhea, length of hospital stay in days and frequency of need for rehydration. No adverse effects were reported.
The investigators say the strengths of the study include “adequate randomization, the use of a double-blind design, comprehensive follow-up, and the use of intention-to-treat analysis, all of which minimize the risk of bias.” However, considering the negative findings, one limitation is the lack of analysis of fecal L reuteri DSM 17938 in order to confirm compliance with administration, they say.
The investigators note that the lack of an effect may be explained by several factors, mainly related to the probiotic itself. “First, the wrong selection of the probiotic strain for a given clinical situation may lead to the lack of an effect. Documented efficacy in one condition, ie colic in infants, as in the case of L reuteri DSM 17938, does not guarantee efficacy in another condition.”
Second, an inadequate probiotic dose may also be to blame for the lack of an effect. The children in the probiotic arm got the manufacturer-recommended daily dose of L reuteri DSM 17938, although “the optimal dose has not been clearly established for either this or other probiotics,” the authors note. “One could not exclude the possibility that a higher dose may be needed for preventing diarrheal diseases.”
“The choice of probiotics, or dose, may explain lack of effect,” Dr. Szajewska added in her email to Reuters Health. “To explore the latter, further studies are needed; we are working on it.”