背景:最近,已经在成人中确定了复发性尿路感染(UTI)与尿微生物组(尿群)组成之间的关联.然而,人们对儿童的泌尿系统知之甚少。我们旨在表征具有物种水平分辨率的儿童的泌尿系,并根据UTI历史确定关联。
方法:54名3个月至11岁的儿童(31名女性和21名男性)参与了这项研究。从接受临床指示的排尿膀胱尿道造影检查的儿童获得了导管尿标本。为了提高对小儿泌尿系的分析,我们使用一种新的方案,使用过滤器从尿液中收集生物量,并结合合成的长读16SrRNA基因测序,以获得与培养无关的物种水平分辨率数据.我们使用对单个细菌和α多样性测量的非参数检验来测试性别和UTI病史之间的微生物组成差异。
结果:我们在54名儿童(平均年龄40.7个月,57%的女性)。和成年人一样,泌尿系生物群在个体之间是不同的,并且因性别而异。通过反辛普森指数和香农指数衡量,雌性的尿生物群落表现出更高的多样性,但皮耶鲁均匀度指数或观察到的物种数却没有(分别为p=0.05,p=0.04,p=0.35和p=0.11)。此外,与雄性相比,雌性中的几种物种明显过多,包括来自缺氧球菌属的那些,普雷沃氏菌,和Schaalia(p分别为0.03、0.04和0.02)。泌尿生物多样性随着年龄的增长而增加,主要由男性驱动。有1、2或3个UTI病史的儿童的比较显示,根据辛普森的测量,在经历3个UTI的组中,尿系多样性显着降低。香农,和Pielou指数(p=0.03,p=0.05,p=0.01)。还发现几种细菌的丰度减少。
结论:在这项研究中,我们证实,从3个月大的婴儿的导管收集的尿液标本中可以识别出尿路生物,提供进一步的证据表明小儿膀胱不是无菌的。除了确认与性别相关的尿路生物群的变化,我们确定了5岁以下儿童的年龄相关变化,这与之前的一些研究相冲突。我们还确定了与UTI历史的关联。
结论:我们的研究提供了更多的证据表明小儿尿路生物存在。儿童膀胱中的细菌似乎受到早期泌尿系统事件的影响,值得进一步研究。
BACKGROUND: Recently, associations between recurrent urinary tract infections (UTI) and the urinary microbiome (
urobiome) composition have been identified in adults. However, little is known about the
urobiome in children. We aimed to characterize the
urobiome of children with species-level resolution and to identify associations based on UTI history.
METHODS: Fifty-four children (31 females and 21 males) from 3 months to 11 years of age participated in the study. Catheterized urine specimens were obtained from children undergoing a clinically indicated voiding cystourethrogram. To improve the analysis of the pediatric
urobiome, we used a novel protocol using filters to collect biomass from the urine coupled with synthetic long-read 16S rRNA gene sequencing to obtain culture-independent species-level resolution data. We tested for differences in microbial composition between sex and history of UTIs using non-parametric tests on individual bacteria and alpha diversity measures.
RESULTS: We detected bacteria in 61% of samples from 54 children (mean age 40.7 months, 57% females). Similar to adults, urobiomes were distinct across individuals and varied by sex. The urobiome of females showed higher diversity as measured by the inverse Simpson and Shannon indices but not the Pielou evenness index or number of observed species (p = 0.05, p = 0.04, p = 0.35, and p = 0.11, respectively). Additionally, several species were significantly overrepresented in females compared to males, including those from the genera Anaerococcus, Prevotella, and Schaalia (p = 0.03, 0.04, and 0.02, respectively).
Urobiome diversity increased with age, driven mainly by males. Comparison of children with a history of 1, 2, or 3+ UTIs revealed that urobiome diversity significantly decreases in the group that experienced 3+ UTIs as measured by the Simpson, Shannon, and Pielou indices (p = 0.03, p = 0.05, p = 0.01). Several bacteria were also found to be reduced in abundance.
CONCLUSIONS: In this study, we confirm that urobiome can be identified from catheter-collected urine specimens in infants as young as 3 months, providing further evidence that the pediatric bladder is not sterile. In addition to confirming variations in the urobiome related to sex, we identify age-related changes in children under 5 years of age, which conflicts with some prior research. We additionally identify associations with a history of UTIs.
CONCLUSIONS: Our study provides additional evidence that the pediatric urobiome exists. The bacteria in the bladder of children appear to be affected by early urologic events and warrants future research.