Grant: Operating Grant

Background: Worldwide, acute gastroenteritis (AGE), which presents as vomiting and diarrhea, is a leading cause of hospitalization and death in children. Each year, Canadians suffer from 5 million episodes of AGE. The majority of episodes are caused by viruses, and a small proportion by bacteria. Currently, treatment options are limited. Consuming good bacteria, called probiotics, may shorten the course of disease and facilitate healing from AGE. In November 2013, we began a CIHR funded study to determine if probiotics are indeed beneficial in AGE. Over the next 4 years, 886 Children aged 3 months to 4 years presenting to one of 5 participating Canadian emergency departments (ED) will receive a probiotic or a placebo for 5 days. The study will evaluate if those receiving probiotic recover faster. It is likely that improvement will depend on the type of infection (e.g. bacteria vs. virus) and the specific pathogen. The current application proposes to expand our work to include expanded microbiology and immunologic testing to better understand how the disease, the therapy and the immune system of the sick child interact so recovery can be optimized. Study Design/Objectives: We will collect stool samples from participating children on the day of ED presentation and again 5 days later. We will test the samples for infections by viruses and bacteria. The quantity of virus and bacteria in stool specimens will be determined and compared between the start and end of treatment. We will use this information to determine to what extent each virus/bacteria is eliminated by probiotics. We will correlate the degree of virus elimination from stool with clinical improvement and with changes in the immune response by quantifying immune markers in the stool. Significance: The knowledge gained will guide how to best to use probiotics, particularly, where the causative pathogens can be rapidly identified and treatment tailored to the individual patient.