We previously described the existence of the pediatric urobiome in both males and females [1]. We now wish to determine if there are differences in the pediatric urobiome by age, and mode of birth delivery dichotomized by sex. Prior studies have demonstrated that the pediatric gut microbiome differs between children delivered by Caesarian section (C-section) and those delivered vaginally. This difference is apparent in the first few months following birth, but within a year the difference becomes much less apparent [2]. Other studies have reported age effects on the gut microbiome [3]. However, to date, the influence of mode of delivery on the pediatric urinary microbiome and the longevity of its potential effects have not been studied.

Following IRB approval, catheterized urine samples from children less than 18 years of age without antibiotic exposure were obtained. Demographic information from the participants were obtained, including mode of birth and age. Urine specimens were assessed using the expanded quantitative urine culture (EQUC) protocol and the isolated bacteria were identified via MALDI-TOF Mass Spectrometry. Following identification, urotype was assigned based on dominant genus (i.e., 50% or greater relative abundance). Microbiome data in terms of urotype were then analyzed by age and by mode of birth delivery. The participants were sorted into three age groups 0-2 years of age, 3-11 years of age, and 12-18 years of age. Significance was determined via Fisher’s exact test.

86 children were included in the study, including 39 females and 47 males. Mean patient age was 6.5 years (2 months – 17 years). Cultivatable bacteria were detected in the bladders of children as young as 2 months old (Figure 1). Whereas most genera were detected in all three age groups, some were only detected in infants or teenagers. Urotypes in terms of sex and mode of birth delivery are listed in Table 1. In males, we detected an association between the Enterococcus-dominant urobiome and delivery by C-section (p=0.02).

Differences were observed in the urinary microbiome by age. We only detected certain genera in the very young (i.e. Finegoldia and Morganella) and some in older children; in particular, Lactobacillus was only detected in females aged eight and older and predominantly in those aged 12 and older. Many genera were detected throughout childhood (especially Actinomyces, Enterococcus, Streptococcus, and Staphylococcus). 

Like other pediatric microbiomes, based upon our pilot study, there appears to be a difference in the bacteria that constitute the urobiome between children born by C-section and vaginal delivery.  Further sample collection will be necessary to confirm this observation and to see if there are other urotypes, genera, or species that are associated with either method of delivery.  In studies examining mode of delivery and the gut microbiome, initial differences quickly disappear with age. At this point, we do not have the statistical power to determine if the differences we see remain with age; we need to increase our sample size.

Detection of some genera seems to be associated with age. A statistically significant association exists between C-section birth in males and the Enterococcus urotype. Increased sampling is required to determine if there are more associations with mode of delivery.

Thomas M Halverson, Denise Juhr, Zachery Kornberg, Hillary Copp, Douglas Storm, and Alan J Wolfe. Presence of Cultivatable Bacteria in the Bladders of children. International Continence Society (ICS) 2019, Gothenburg, Sweden, September 3-6 2019
Reyman M, van Houten MA, van Baarle D, et al. Impact of delivery mode-associated gut microbiota dynamics on health in the first year of life [published correction appears in Nat Commun. 2019 Nov 25;10(1):5352]. Nat Commun. 2019;10(1):4997. Published 2019 Nov 1. doi:10.1038/s41467-019-13014-7
O'Toole PW, Jeffery IB. Gut microbiota and aging. Science. 2015;350(6265):1214–1215. doi:10.1126/science.aac8469