Stearns Jennifer C, Davidson Carla J, McKeon Suzanne, Whelan Fiona J, Fontes Michelle E, Schryvers Anthony B, Bowdish Dawn M E, Kellner James D, Surette Michael G
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
ISME J. 2015 May;9(5):1246-59. doi: 10.1038/ismej.2014.250. Epub 2015 Jan 9.
The upper respiratory tract (URT) is a crucial site for host defense, as it is home to bacterial communities that both modulate host immune defense and serve as a reservoir of potential pathogens. Young children are at high risk of respiratory illness, yet the composition of their URT microbiota is not well understood. Microbial profiling of the respiratory tract has traditionally focused on culturing common respiratory pathogens, whereas recent culture-independent microbiome profiling can only report the relative abundance of bacterial populations. In the current study, we used both molecular profiling of the bacterial 16S rRNA gene and laboratory culture to examine the bacterial diversity from the oropharynx and nasopharynx of 51 healthy children with a median age of 1.1 years (range 1-4.5 years) along with 19 accompanying parents. The resulting profiles suggest that in young children the nasopharyngeal microbiota, much like the gastrointestinal tract microbiome, changes from an immature state, where it is colonized by a few dominant taxa, to a more diverse state as it matures to resemble the adult microbiota. Importantly, this difference in bacterial diversity between adults and children accompanies a change in bacterial load of three orders of magnitude. This indicates that the bacterial communities in the nasopharynx of young children have a fundamentally different structure from those in adults and suggests that maturation of this community occurs sometime during the first few years of life, a period that includes ages at which children are at the highest risk for respiratory disease.
上呼吸道（URT）是宿主防御的关键部位，因为它是细菌群落的栖息地，这些细菌群落既能调节宿主免疫防御，又可作为潜在病原体的储存库。幼儿患呼吸道疾病的风险很高，但人们对其URT微生物群的组成了解并不充分。传统上，呼吸道微生物分析主要集中于培养常见的呼吸道病原体，而最近不依赖培养的微生物组分析只能报告细菌种群的相对丰度。在本研究中，我们使用细菌16S rRNA基因的分子分析和实验室培养，来检测51名健康儿童（中位年龄1.1岁，范围1 - 4.5岁）以及19名陪同家长的口咽和鼻咽部的细菌多样性。结果表明，在幼儿中，鼻咽微生物群与胃肠道微生物群非常相似，从由少数优势类群定殖的不成熟状态，发展为成熟时更具多样性的状态，类似于成人微生物群。重要的是，成人和儿童之间细菌多样性的这种差异伴随着细菌载量三个数量级的变化。这表明幼儿鼻咽部的细菌群落结构与成人的根本不同，并表明该群落的成熟在生命的最初几年的某个时候发生，这一时期包括儿童患呼吸道疾病风险最高的年龄段。
