The Impact of Probiotics in the Respiratory and Gastrointestinal Microbiome and Its Role in Respiratory Tract Infections in Children

Pneumonia and diarrhea are the most frequent causes of infectious diseases in children under 5 years of age worldwide, responsible for 1.5 million deaths annually.

In up to 80% of pneumonia cases the etiology is viral. Some viruses can persist up to 6 months after an acute infection. The time when viruses enter the body and whether they are commensals or only cause disease and are eliminated after an acute infection is unknown.

Modern techniques have identified diverse communities of microbiota in healthy and sick people, and viral communities associated in a close interaction. The acquisition and colonization by respiratory viruses and the role in health and disease in this niche that is the microbiome is unknown.

The role of probiotics in the prevention of respiratory disease and in the maintenance of homeostasis in the microbiota is poorly understood, and even more the probable relationship between the microbiota, the respiratory viruses that could be commensals or pathogens at the respiratory level, the time when children can be colonized, and their regulation with the administration of probiotics.

The aims of the study are to determine the changes in the intestinal and respiratory microbiota, the viruses that can be commensals or cause disease and the role of probiotics in the prevention of respiratory diseases during the first year of life.

A prospective, randomized, controlled clinical trial will be carried out making basic metagenomics studies (translational medicine). After informed consent, 120 newborns will be randomized into 2 groups, one will receive probiotics 4 times a week orally and the other a placebo consisting of sterile water 4 times a week. The clinical follow up will be done every 2 months until 1 year old, nasal washes and stool samples will be collected to determine the intestinal and respiratory microbiome. Multiplex polymerase chain reaction studies will be conducted to detect the presence of respiratory viruses and the time when the children acquire viruses that are commensal or only in the case of respiratory infection. The mothers will be asked to come for consult in case of respiratory infection and a nasal wash and stool sample will be taken. Descriptive, bivariate and multivariate statistics will be used to determine the associations between the microbiota, the viral metagenomics, the respiratory viruses and the risk of presenting or not respiratory infection in the group receiving probiotics compared to placebo.