Altered Gut Microbiota in Infants is Associated with Respiratory Syncytial Virus Disease Severity
Abstract RationaleRespiratory syncytial virus (RSV) is the number one cause of lower respiratory tract infections in infants. There are still no vaccines or specific antiviral therapies against RSV, mainly due to the inadequate understanding of RSV pathogenesis. Recent data suggest a role for gut microbiota community structure in determining RSV disease severity.ObjectivesOur objective was to determine the gut microbial profile associated with severe RSV patients, which could be used to help identify at-risk patients and develop therapeutically protective microbial assemblages that may stimulate immuno-protection.MethodsWe enrolled 58 infants hospitalized with RSV, all were admitted to the pediatric ward. 53 remained in the pediatric ward (moderate) and 5 were moved to the pediatric intensive care unit at a later date (severe). We also enrolled 37 healthy infants during their “well-baby checkups” from 2012 to 2015. We evaluated the composition of gut microbiota from stool samples collected within 72 hours of enrollment via 16s sequencing of fecal DNA.Measurements and Main ResultsThere was a significant enrichment in S24_7, Clostridiales, Odoribacteraceae, Lactobacillaceae, and Actinomyces in RSV (moderate and severe) vs. controls. Patients with severe RSV disease had slightly lower alpha diversity (richness and evenness of the bacterial community) of the gut microbiota compared to patients with moderate RSV and healthy controls. Beta diversity (overall microbial composition) was significantly different between all RSV patients (moderate and severe) compared to controls and had significant microbial composition separating all three groups (control, moderate RSV, and severe RSV).ConclusionsCollectively, these data demonstrate that a unique gut microbial profile is associated with severe RSV disease prior to admission to the pediatric intensive care unit. More mechanistic experiments are needed to determine whether the differences observed in gut microbiota are the cause or consequences of severe RSV disease.