Description of the voided urinary microbiota in asymptomatic prepubertal children - A pilot study

Survey of the infant male urobiome and genomic analysis of Actinotignum spp

The urinary bladder harbors a community of microbes termed the urobiome, which remains understudied. In this study, we present the urobiome of healthy infant males from samples collected by transurethral catheterization. Using a combination of enhanced culture and amplicon sequencing, we identify several common bacterial genera that can be further investigated for their effects on urinary health across the lifespan. Many genera were shared between all samples suggesting a consistent urobiome composition among this cohort. We note that, for this cohort, early life exposures including mode of birth (vaginal vs. Cesarean section), or prior antibiotic exposure did not influence urobiome composition. In addition, we report the isolation of culturable bacteria from the bladders of these infant males, including Actinotignum spp., a bacterial genus that has been associated with urinary tract infections in older male adults. Herein, we isolate and sequence 9 distinct strains of Actinotignum spp. enhancing the genomic knowledge surrounding this genus and opening avenues for delineating the microbiology of this urobiome constituent. Furthermore, we present a framework for using the combination of culture-dependent and sequencing methodologies for uncovering mechanisms in the urobiome.

In-depth metataxonomic investigation reveals low richness, high intervariability, and diverse phylotype candidates of archaea in the human urogenital tract

The urogenital microbiota is the potential principal factor in the pathophysiology of urinary tract infection and the protection of urinary tract health. Little is known about the urogenital archaeome although several reports have indicated that the archaeomes of various regions of the human body are associated with health. Accordingly, we aimed to determine the presence and diversity of archaeomes in the human urogenital tract. To explore the urogenital archaeome, voided urine specimens from 373 asymptomatic Korean individuals were used. No difference was observed in body mass index, age, or gender, according to presence of archaea. Analysis of archaeal 16S rRNA gene amplicons of archaea positive samples consisted of simple community structures, including diverse archaea, such as the phyla Methanobacteriota, Thermoproteota, and Halobacteriota. Asymptomatic individuals showed high participant-dependent intervariability in their urogenital archaeomes. The mean relative archaeal abundance was estimated to be 0.89%, and fluorescence in situ hybridisation micrographs provided evidence of archaeal cells in the human urogenital tract. In addition, the urogenital archaeome shared partial taxonomic compositional characteristics with those of the other body sites. In this study, Methanobacteriota, Thermoproteota, and Halobacteriota were suggested as inhabitants of the human urogenital tract, and a distinct human urogenital archaeome was characterised. These findings expand our knowledge of archaea-host associations in the human urogenital tract and may lead to novel insights into the role of archaea in urinary tract health.

Sexual behavior shapes male genitourinary microbiome composition

The origin, composition, and significance of the distal male urethral microbiome are unclear, but vaginal microbiome dysbiosis is linked to new sex partners and several urogynecological syndromes. We characterized 110 urethral specimens from men without urethral symptoms, infections, or inflammation using shotgun metagenomics. Most urethral specimens contain characteristic lactic acid bacteria and Corynebacterium spp. In contrast, several bacteria associated with vaginal dysbiosis were present only in specimens from men who reported vaginal intercourse. Sexual behavior, but not other evaluated behavioral, demographic, or clinical variables, strongly associated with inter-specimen variance in urethral microbiome composition. Thus, the male urethra supports a simple core microbiome that is established independent of sexual exposures but can be re-shaped by vaginal sex. Overall, the results suggest that urogenital microbiology and sexual behavior are inexorably intertwined, and show that the male urethra harbors female urogenital pathobionts.

Cranberry-lingonberry juice affects the gut and urinary microbiome in children - a randomized controlled trial

The mechanism by which cranberry-lingonberry juice (CLJ) prevents urinary tract infections (UTI) in children remains unknown. We hypothesized that it alters the composition of the gut or urinary microbiome. Altogether, 113 children with UTIs were randomly allocated to drink either CLJ or a placebo juice for 6 months. We collected urinary samples at 3 months and fecal samples at 3, 6 and 12 months and used next-generation sequencing of the bacterial 16S gene. The children who consumed CLJ had a lower abundance of Proteobacteria (p = 0.03) and a higher abundance of Firmicutes phylum (p = 0.04) in their urinary microbiome at 3 months than did those in the placebo group. The abundance of Escherichia coli in the urinary microbiome was 6% in the CLJ group and 13% in the placebo group (p = 0.42). In the gut microbiome the abundance of Actinobacteria at 3 and 12 months was higher in the children receiving CLJ. The diversity of the urinary and gut microbiome did not differ between the groups. The children drinking CLJ had a different urinary and gut microbiome from those receiving a placebo juice. A healthy urinary microbiome may be important in preventing UTIs in children.

The pediatric urobiome in genitourinary conditions: a narrative review

The microbial ecosystem within the bladder that can be measured within the urine, or urobiome, is an emerging field of study with little published data regarding children. However, investigations into urobiome research have the potential to significantly impact the understanding of the pathophysiology of genitourinary conditions, as well as potentially identify novel therapeutics. Therefore, both researchers and clinicians should be aware of pediatric urobiome research. The purpose of this review is to highlight the literature around urobiome research in urinary tract infections, nephrolithiasis, and neurogenic bladder; comment on pediatric-specific considerations when reading and interpreting the urobiome literature; and to identify new potential areas of research.

A Child's urine is not sterile: A pilot study evaluating the Pediatric Urinary Microbiome

INTRODUCTION

A bladder microbiome (urobiome) exists in adults. Data supports the effects of the adult urobiome on urinary tract health with associations between dysbiotic urobiomes and lower urinary tract disorders. Understanding urobiome origin is important since other microbiomes establish around birth and microbiome alterations are linked to disease development. However, the pediatric urobiome has not been well studied.

OBJECTIVES

We sought to determine the age when the urobiome develops, compare the pediatric urobiome to microbiomes of adjacent urogenital niches, and compare the urobiomes between boys and girls and across age groups.

STUDY DESIGN

Seventy-four children less than 18 years of age without recent antibiotic exposure were recruited, including 48 males and 26 females, aged 2 weeks to 209 months of age. Transurethral catheterized urine samples and samples from the perineum, urethra, vagina, and foreskin were collected. Specimens were assessed using the expanded quantitative urine culture protocol and by 16S rRNA gene sequencing. Dada2 was used to profile microbial compositions, and BLCA was used to identify microbial taxa.

RESULTS

Bacteria were detected in 90.5% of urine samples and identified in children as young as 2 weeks of age. Microbial communities and compositions of the female bladder and other urogenital niches (urethra, perineum, and vagina) differed significantly by age. Lactobacillus predominated the bladder, urethral, and vaginal microbiomes in post-pubertal girls. Compared to female urinary microbiomes, those of males differed less substantially. Only perineal microbiomes differed significantly by age, whereas male urethral and foreskin microbiomes did not differ significantly.

DISCUSSION

We identified that a urinary microbiome is established as early as infancy. In addition, the female urobiome changes throughout childhood, until the post-pubertal bacterial taxa becomes consistent with that seen in adult females. Whereas in boys, the urinary microbiome changed very little over time. In addition, the surrounding urogenital microbiomes differed less in boys as compared to females. Microbiomes established at a young age may have long-term influences on immune, metabolic, and neurobehavioral traits. The same may be true for the urobiome. Our study provides a foundation for future research to determine the influence of the pediatric urobiome on the development of urinary and even non-urinary disorders.

CONCLUSIONS

A pediatric urobiome exists, with differences between males and females and can be detected at a young age with changes occurring throughout childhood. Similarities and differences are also seen between the pediatric urobiome and adjacent niches.

Emerging Role of Microbiome in the Prevention of Urinary Tract Infections in Children

The microbiome of the urinary tract plays a significant role in maintaining health through the impact on bladder homeostasis. Urobiome is of great importance in maintaining the urothelial integrity and preventing urinary tract infection (UTI), as well as promoting local immune function. Dysbiosis in this area has been linked to an increased risk of UTIs, nephrolithiasis, and dysfunction of the lower urinary tract. However, the number of studies in the pediatric population is limited, thus the characteristic of the urobiome in children, its role in a child's health, and pediatric urologic diseases are not completely understood. This review aims to characterize the healthy urobiome in children, the role of dysbiosis in urinary tract infection, and to summarize the strategies to modification and reshape disease-prone microbiomes in pediatric patients with recurrent urinary tract infections.