Respiratory microbiota imbalance in children with Mycoplasma pneumoniae pneumonia

Abstract

Although previous studies have reported the dysregulation of respiratory tract microbiota in infectious diseases, insufficient data exist regarding respiratory microbiota imbalances in the lower respiratory tracts (LRTs) of children with Mycoplasma pneumoniae pneumonia (MPP). Here, we analysed the microbial community using 16S rRNA gene sequencing. Finally, bronchoalveolar lavage fluid (BALF) samples from 158 children with MPP and 29 with bacterial or viral pneumonia (control group) were collected. The diversity of the microbial community was significantly different between the two groups. A significantly increased abundance of Tenericutes and Mycoplasma was detected in the MPP group, exceeding 67% and 65% of the total bacterial population, respectively. Using Mycoplasma abundance as the diagnostic method, the sensitivity and specificity of the model was 97.5% and 96.6%, respectively. Compared to the mild MPP group, lower alpha diversity and significantly increased Mycoplasma abundance were found in the severe MPP group (P < 0.01). The abundance of Mycoplasma was positively correlated with complications and clinical indices in children with severe MPP compared with children with mild MPP. Our study describes the features of the LRT microbiota of children with MPP and uncovered its association with disease severity. This finding may offer insights into the pathogenesis of MPP in children.

Keywords: 16S rRNA gene; Children; Mycoplasma pneumoniae pneumonia; Respiratory microbiota; lower respiratory tract.

Figure 1.

Forest plot for the risk factors associated with MPP when compared with the control group. The odds ratio (OR) was based on the logistic regression model and adjusted for a potential confounding factor (age). MPP, Mycoplasma pneumoniae pneumonia patient; Control, other bacterial or viral pneumonia; CI, confidence interval.

Figure 2.

Comparisons of respiratory microbiota in MPP and Control groups. (A) Alpha diversity was evaluated by the Shannon index. (B) Alpha diversity was evaluated by the Simpson index. (C) Principal coordinate analysis based on the Weighted Unifrac matrix between MPP and Control groups. (D) Relative abundance of respiratory microbiota at the phylum and genus level. (E) The species with significant differences in abundance between the two groups by using LEfSe analysis. MPP, Mycoplasma pneumoniae pneumonia patient; Control, other bacterial or viral pneumonia. **P < 0.01, ***P < 0.001.

Figure 3.

Comparisons of respiratory microbiota in Control, severe MPP, and mild MPP groups. (A) Alpha diversity was evaluated by the Shannon index. (B) Alpha diversity was evaluated by the Simpson index. (C) Principal coordinate analysis based on the Weighted Unifrac matrix. (D) Relative abundance of respiratory microbiota at the phylum and genus level. (E) The species with significant differences in abundance between the mild and severe MPP groups by using LEfSe analysis. MPP, Mycoplasma pneumoniae pneumonia patient; Control, other bacterial or viral pneumonia. ***P < 0.001.

Figure 4.

Comparisons of respiratory microbiota in MPP children enrolled based on different diagnostic standard. (A) Alpha diversity was evaluated by the Shannon index. (B) Principal coordinate analysis based on the Weighted Unifrac matrix. (C) Relative abundance of respiratory microbiota at the phylum level. (D) Relative abundance of respiratory microbiota at the genus level. NS, no significance.

Figure 5.

Relative abundance of Tenericutes, Mycoplasmataceae and Mycoplasma in MPP and Control groups. (A) Tenericutes. (B) Mycoplasmataceae. (C) Mycoplasma. MPP, Mycoplasma pneumoniae pneumonia patient; Control, other bacterial or viral pneumonia. ***P < 0.001.

Figure 6.

Relative abundance at the genus level of the children with discordant diagnosis based on the clinical diagnosis and Mycoplasma abundance.

Figure 7.

Correlation networks between microbiota and disease severity. (A) Concordance of the MP abundance and complication numbers. (B) Correlation between the different abundance of respiratory microbiota at the genus level and the clinical indices in children with severe MPP when compared with mild MPP.