Microbiota Composition in Upper Respiratory Tracts of Healthy Children in Shenzhen, China, Differed with Respiratory Sites and Ages

Abstract

The upper respiratory tract (URT) is home to various microbial commensals, which function as competitors to pathogens and help train the immune system. However, few studies have reported the normal microbiota carriage in the URT of healthy Chinese children. In this study, we performed a 16S rDNA gene sequencing analysis of 83 anterior nares (ANs), 60 nasopharynx (NP), and 97 oropharynx (OP) samples from 98 healthy children in Shenzhen, China (≤12 years of age). The microbiota in ANs and NP is the same at different ages and typical species in these sites include Moraxella, Staphylococcus, Corynebacterium, Streptococcus, and Dolosigranulum. By contrast, the OP is primarily colonized by Streptococcus, Prevotella, Neisseria, Veillonella, Rothia, Leptotrichia, and Haemophilus. Streptococcus and Rothia keep low abundance in OP microbiota of children ≤1 year old, whereas Prevotella, Neisseria, Haemophilus, and Leptotrichia amass significantly in individuals >1 year old. This work furnishes an important reference for understanding microbial dysbiosis in the URT of Chinese paediatric patients.

Figure 1

Microbial flora in the ANs, NP, and OP are differentiated at different ages. (a) The top 5 genera among the ANs and NP were Moraxella, Staphylococcus, Corynebacterium, Streptococcus, and Dolosigranulum, and OP harboured different dominant genera. (b) The microbiota composition of the OP remained different from those of the ANs and NP. In each subgroup ((c) ≤1 year old; (d) >1 and ≤3 years old; (e) >3 and ≤6 years old; (f) >6 years old), all OP samples exhibited an independent cluster other than mixed ANs and NP. Each genus was painted with specific colours.

Figure 2

Microbial diversity in the ANs, NP, and OP at different ages and dominated genera in the OP of children ≤1, >1 and ≤3, or >3 years old. (a) The microbial diversity in the OP increased significantly during the first year of life and then remained stable, ANs and NP shown to be similar microbial diversity at different age. NS, ∗, and ∗∗∗ represent p-value >0.05, ≤0.05, and ≤0.001, respectively. (b) Structure of dominant genera based on relative abundance. Each circle represents genus with total relative abundance in the three groups, and the width of line represents genus with the relative abundance in each group. ∗∗ and ∗∗∗ represent q-value of Kruskal-Wallis test ⩽ 0.01 and ⩽ 0.001, respectively.