Assessment of the Urinary Microbiome in Children Younger Than 48 Months

Background: The urinary tract was once thought to be sterile, and little is known about the urinary microbiome in children. This study aimed to examine the urinary microbiome of young children across demographic and clinical factors. Methods: Children <48 months, undergoing a urinary catheterization for clinical purposes in the Pediatric Emergency Department were recruited and urine samples collected. Detailed demographic and clinical information were recorded. Urine samples underwent DNA extraction and 16S ribosomal RNA gene sequencing, urinalysis and urine culture. Results: Eighty-five children were included; a urinary microbiome was identified in every child. Nine children had Escherichia coli urinary tract infections (UTIs) identified. Those with UTIs had a significantly decreased alpha diversity ( t test, P < 0.001) and the composition of the microbiome clustered separately ( P = 0.001) compared with those without UTIs. Conclusions: A urinary microbiome was identified in every child, even neonates. Differences in microbiome diversity and composition were observed in patients with a standard culture positive UTI. The urinary microbiome has just begun to be explored, and the implications on long-term disease processes deserve further investigation.